Serving Timex-Sinclair Personal Computers

A PUBLICATION OF THE HARVARD GROUP

VOL. 3 NO. 11 ISSN 0273-2696 NOV., 1982

IN THIS ISSUE

8K Programs

Boolean Demonstration. 17

Dec. -Hex. Conversion. .. 9

Etching Program . 3

Pie Chart Graph and

Display . 6

Self-running Programs.. 4 Solar Program for Flat

Plate Collectors . 8

Star Hunter . 6

Two Numbers in

One Byte . 19

Book Review

ZX81 BASIC Book . 5

Classified Ads . 19

Dear Editor . 12

Hardware Project

Switch Box . 15

Hardware Reviews

Byte-Back Modem . 18

Computer Keyboards Kit

and Enclosure . 16

QSAVE . 4

Machine Code Programming Storing MC Routines

in REM . 10

News, New Products. ... 1 ,2 Software Reviews

QSAVE . 4

ZX81 Home Computer

Package . 11

Syntax Errors . 2

Users' Groups . 13

Index of Advertisers

Byte-Back Co . 16

Cases Inc . 11

Dallas Development . 7

Memotech Corp . 14

Mindware Inc . 3

Rist Computers . 17

Softsync Inc . 15

TIMEX PRINTER AND MODEM INFO

Timex's 40-column thermal printer will be available in Dec. 82 for $99.95, says Timex VP Danny Ross. Despite its 40-column format, it LLISTs in screen format (32-col). The printer needs no interface and has its own power supply. Printer also uses the keyboard print commands. Ross also said Timex's new 300-baud modem will be ready first quarter of '83. Some features: autodial and answer and software to let ZX/TS computers communicate with other kinds of computers, making commer¬ cial data bases accessible to ZX/TS users.

TS1000 SERVICE CENTER AND COMPUTER HOTLINE

Timex's repair address: Timex Service Center, 7004 Murray St., POB K, Little Rock, AR. New hotline number for computer prod¬ ucts: 800/248-4639. Call 8am-llpm Mon.-

Fri.; 9am-9pm Sat. and Sun.

CAI OFFERS COMPUTER NETWORK PACKAGE

CAI now offers a network package includ¬ ing Lexicon 11 modem, ASCII modem and cable. Package (not direct-connect): $149.95+$2.95

P&H. Separately, network package items are: Lexicon modem $129.95, ASCII modem $24.95 and cable $9.95. CAI's direct-connect phone modem is $149.95. CAI Instruments, P.O. Box 2032, Midland, MI 48640.

MACRONICS ANNOUNCES FLOPPY DISK INTERFACE

Run a 5 1/4" disk drive with your ZX/TS and Macronic's new FIZ 1.1 interface. Inter¬ face plugs into rear edge connector with an expansion bus. FIZ interface, $149, expan¬ sion bus $35. Assembled and cased 5 1/4" drive with 110V 60Hz supply is $330 extra. Prices include airmail postage. Macronics,

26 Spiers Close, Knowle, Solihull, West Midlands B93 9ES UK.

SECOND ANNIVERSARY ISSUE

NEW PRODUCTS

ADDRESSES (with 16K available) can store 133 addresses (90 chars, each) or other data. You get 36 codes for search and listing. En¬ tries can be made and changed and users familiar with BASIC can modi¬ fy this program to suit their own needs. ACCR is a payment receipt reminder. With 16K it stores 266 entries of date, name (20 char.) and amount. It searches by code, month or name. ACCP, companion program for ACCR, works similarly and is useable for accounts pay¬ able. Tapes are $19.95 or 3 for $39.90. R.S. Panwar, 2035 Kentland Dr., Houston, TX 77067, 713/537- 8453 (6-9 pm).

Nonvolatile Memory and I/O Ports give 6 parallel I/O ports to inter¬ face your ZX/TS to other devices.

It also has sockets for up to 4 extra memories, either 2716 EPROMs, 2Kx8 static RAM or 2Kx8 nonvolatile memories or EPROM to store your own USR programs. Your Sinclair/Timex RAM plugs directly on. $79 kit,

$99 assembled and tested. EPROM Programmer, $79 with hardware and software to program 2716 EPROMs. Wisconsin Electronics, Box 332, Milton, WI 53563.

SALES-PLUS shows TS1000 selling points. It can be factory-custom¬ ized to present retailer's name with Timex name. $17.95 in quanti¬ ty (300) including customization. Development Assoc., 1520 S. Lyon, Santa Ana, CA 92705, 714/835-9512.

Z EXTRA, a ZX/TS graphics control program (needs SLOW mode, 16K RAM min.), provides: keyboard control of graphic and display features, storage of info into high RAM for future reference, revision, or dis¬ play; screen storage in "collapsed" format so you can store 60-80 screens in the top 40K of a 64K memory, menu-driven screen file handling, blinking cursors, repeat¬

ing keys, 4 write directions for letters or graphics characters, 8 plot directions for pixel drawing, 4x4 and 8x8 char, sizes, plus in¬ sert, delete, search and other editing functions. Z EXTRA is user-configurable for 16-64K RAMs and can be set to use only part of your memory. Tape and instructions $19.95 ppd. from Sinware, Box 323, Dixon, NM 87501.

Tape Loader (TL-064) and Heat Controller (OP-032) , announced Oct. SYNTAX, go up Nov. 1: TL-064 will

be $22.95 and OP-032 will be $15.95. P. Pollack, 6240 Halifax St., N.Burnby, BC Canada V5B 2P6.

Z80 System Reference Card offers formulas to calculate your own timing with any MHz; condition code chart and hex-to-decimal chart; undocumented op-codes for some chips; instructions in op-code se¬ quence for PEEKing, and in mnemonic sequence for POKEing with decimal equivalents, $4.95. Nanos Systems, Bx 24344, Speedway, IN 46224.

SYNTAX ERRORS: Grading Program, Oct. 82, indicated line 240 as the round-up cut-off routine. Line 210 is the round-up cut-off routine.

In Unit Pricer, Oct. 82, line 84 should read as line 20. Line 4241 should read as line 145. Add line 350 STOP.

In my Monthly Calendar program. Sept. 82, the characters "B" in the PRINT statements simply mean to print a blank space.

Herb Cohen, Winchester, KY

In my Hex Math improvement (Oct. 82), line 530 should read:

530 LET H (X) + (INT D-INT Q*16)+28 The line is not elegant in that form. This looks better and works: 520 LET Q+INT (D/16)

530 LET H (X) =INT (D-Q*16)+28

Ronald H. Miller, Murrysville, PA

2

ETCHING PROGRAM — 8K/1K

This program draws patterns by itself. It traces a continuous line, starting at the left-hand center edge of the screen, bouncing off the edges, and stopping only if the line leads into one corner.

ETCH fits in IK RAM. Start the program using RUN (ENTER).

When the cursor appears, enter the slope of the line; 0 yields a horizontal line; 1, a 45 diagonal up; -1, a 45 diagonal down. Values may be any number, including deci¬ mal or fractional values, but those between plus or minus 5 seem to be the most productive.

When an interesting pattern appears, type "M" to pause; hit any key to resume operation.

BREAK followed by ENTER will stop the program. To restart, just press RUN and ENTER again.

David R. Rowland, Montclair, NJ

110

±2©

13©

14-®

16©

165

17©

13©

135

22©

5

= 1 = 2 = Y + i = X + l

235 27©

23©

235 320 35©

«ZT __ .

tjt »ji L— t

LET X=©

LET Y=©

PLOT X., INPUT Z LET U =

LET T =

LET Y LET X GQ5UB 5@0 GOTO 17@

LET U — 0 LET T = 3 LET Y = Y-i LET X = X+l GO SUB 30© GOTO 2"70 LET U = 3 = O

37© LET Y - Y-f4 33© LET X = X*i 335 GOSUB S3©

420 GOTO 370 430 LET U = 2 455 LET T = 1

47© LET Y = Y - I 430 LET X = X-i 455 GOSUB BO©

520 GOTO 470 S00 LET B==20+Z4Y 005 IP INKEY $

1000©

310 IP RSS B >

0 - 100 *T )

02© IP PBS X = S4 THEN GOTO 0 - 100 *U )

030 UNPLOT X.-.B 040 PLOT X j, B 050 RETURN SYNTACTIC SUM:

= "M

THEN PAUSE

43 THEN GOTO C4C

33943,* BK^'SK

FIRST TALK TO

If you’re writing software for the Timex-Sinclair personal computer, you ought to talk first to the software publishing company that will do the most for you and your program. Here’s six good reasons why good programmers come to us first:

1. MASS MARKETING CAPABILITIES.

The Timex-Sinclair computer market is no longer a mail-order, hobbyist business. We have the marketing resources to put your titles in more than 25,000 retail outlets, including chain stores, mass merchandisers, audio centers and PX’s.

2. VERTICAL MARKETING CAPABILITIES.

At the same time, we also sell actively to the kind of specialized audiences who can’t be reached through mass market outlets.

If you’ve written the definitive program for machine shop estimators, we know where to sell it.

3. BETTER ROYALTY TERMS.

Since we expect to buy the best in Timex-Sinclair software, we expect to pay the best in royalties. And we pay promptly and frequently— a policy that, sadly enough, many other publishers seem to feel is unnecessary.

4. “QUICKLOADING”.

Every title we sell now incorporates our unique “Quickload” algorithm. “Quickload” enables your program to load ata rate six times faster than other Timex-Sinclair software. That kind of special feature means bigger sales— and bigger royalties.

5. PROFESSIONAL PACKAGING AND PROMOTION.

We take ourtitles seriously. We’re willing to invest in good graphics, good documentation, good advertising. You’ll be proud to show off your work, because we are too.

6. WE’RE NICE TO DEAL WITH.

Mindware isn’t a big, impersonal corporation with layers of bureaucrats to penetrate. We know our leadership in software depends on finding the very best authors— and keeping them . So we try to respond quickly and honestly, and treat you with respect.

We can’t promise to publish every program you submit. But if you’ve got a title you feel is a real winner, our advice is simple:

FIRST, TALK TO

15 Tech Circle, Natick, Mass. USA 617-655-3388

3

HARDWARE/SOFTWARE REVIEW

Product: QSAVE

From: Personal Software Serv¬ ices, 112 Oliver St., Coventry, U.K. CV6 5FE Price: $30 US (includes P&H)

QSAVE1 s package consists of a small plastic box with four minia¬ ture phone jacks labeled A, B, C and D, two cables with matching plugs, the tape and a manual.

After briefly scanning the manual, I plugged things together, put the tape in my recorder, typed LOAD "" and watched anxiously while nothing happened. I could not find the proper-sized screwdriver to open the shaper-amplifier so I looked more closely at the manual. The ear plug from the recorder goes to A. One short cable goes from B to the computer's ear jack. The power plug goes to C. D goes to the computer's power jack.

After I hooked up everything properly, QSAVE loaded the first time. Almost any tape will load with the shaper-amplifier.

QSAVE automatically moves the machine language (contained in two REM statements) above RAMTOP when it loads. It then prints a short menu listing USR addresses for the SAVE, VERIFY and LOAD calls.

When saving with QSAVE, you can't save programs by name and you can't save self— running programs in QSAVE code. But QSAVE' s speed makes up for these shortcomings.

VERIFY is especially useful. After saving a program in QSAVE code, you can play it back to the computer with the VERIFY command (PRINT USR 32377). The program prints V=0 if everything is OK. Numbers other than zero indicate an improper volume setting or a bad recording. You can re-record be¬ fore turning off the computer.

Once QSAVE is loaded (about 45 seconds), your programs in QSAVE code will load in 29 seconds. You only need to load QSAVE once per

computing session — just don't exe¬ cute a NEW. When you finish with a program, enter the QSAVE Load com¬ mand (PRINT USR 32371) to load another program in QSAVE code. NEW or programs that move machine lan¬ guage above RAMTOP will require re¬ loading QSAVE.

It's convenient to copy QSAVE at the front of tapes containing programs in QSAVE code. To put QSAVE onto another tape, don't type SAVE. To preserve QSAVE's load and execute features, start the record¬ er then type RUN ENTER. QSAVE will save itself.

I am very pleased with QSAVE's package. The hardware definitely aids in loading balky tapes and the time saved in loading long programs is certainly worthwhile.

C. Nunnery, Fort Walton Beach, FL

SELF RUNNING PROGRAMS — 8K

Making a self-running program on the ZX81 is very simple. Just insert a SAVE statement at the place you want the computer to con¬ tinue from. The SAVE statement acts like a CONTinue statement, continuing at the next line with the same variables it left off with. So a self-running program eliminates the need for the user to start the program. It also lets you put executable statements after the SAVE command.

After entering the example, type NEW, LOAD "ZZ" and the screen should display the character set from your keyboard then pause about 2 seconds. This program shows that the ZX/TS saves the screen content, variables and the line the program was saved on.

Chris White, Lake Forest, IL

1© t* Oh h~1 i O hSv> 2© PRINT CHR$ ;

'30 NEXT R 4-0 PfiUSE I@©

50 SPUE ** ZZ“

6© PfiUSE 1©©

5YNT RCT IC SUM *

4-‘34-£ 8K

4

BOOK REVIEW

Title: ZX81 BASIC Book

By: Robin Norman

From: ITT Publishing

Howard W. Sams 4300 W. 62nd St. Indianapolis, IN 46026 317/298-5400

Price: $12.95 (softcover, 192 pp.)

Your ZX81 BASIC Programming book supplied with your ZX81 compu¬ ter documents the hardware and software aspects of the computer, but does not give a thorough enough introduction to BASIC if your ZX/TS is your first computing experience.

Norman begins at the level of the rankest beginner and helps him or her "learn to use all the in¬ structions in ZX81 BASIC using a structured course with a steadily increasing tempo."

Short of teaching someone else, the best way to learn is by doing. This book is excellent proof of that dictum. Chapter by chapter, the learner is given examples to enter and run, and programs to write (with working sample solu¬ tions in an appendix). Chapter summaries itemize specifically what is new in the chapter. I find the style acceptable, the content interesting and informative, and the programs challenging. Begin¬ ners should find much of value in this book.

Appendices include a complete list of all ZX81 BASIC instructions with definitions, a glossary, 14 varied ZX81 programs, sample an¬ swers to program exercises, and directions for expanding to 16K RAM. A thorough index is included.

Norman's book suffers minor problems. There should have been more careful proofreading; mistakes in the text are not too troublesome but typos in programs cause prob¬ lems. Except for "Black Box," these fall into two classes: lack of clarity and consistency about the use of spaces in PRINT strings,

and occasional incorrect use of commas and semicolons.

I ran a good selection, but not all, of the programs listed in Appendix 3. They include IK RAM programs ranging from "Random Rec¬ tangles" and other graphic dis¬ plays, and several mathema-tical programs like "Moving Averages" and "Finding Factors" to interactive graphics like "Drawing Pictures" and "Cows and Bulls" and games like "Electronic Dice" and "Reaction Time." There are 16K RAM versions of "Drawing Pictures," "Telephone List," and "Black Box." In "Black Box" the computer hides 4 atoms in a 64-box matrix. However, the program needs the following correc¬ tions to run satisfactorily:

285, 290, 295, 4230 read 1$ for 1$ 250 PRINT AT 0,22;"WHAT NOW?";

TAB 24 ; "=END"

1190 GOTO 2600 1540 LET Y=Y-1 2440 LET X=X-1

Line 250 lets the display work. Improve it by adding:

7 FAST

190 PAUSE 50 505 GOSUB 3300 3650 PRINT AT 5,26; X 3690 PRINT AT 8,27;4 3765 GOSUB 3300

Toward the end of the preface, Norman comments to all computer users, "You cannot 'read' a book like this. Whatever you get out of it will be the result of a three-way interaction between you, this book, and the ZX81. And if you ever find yourself thinking, 'What would happen if...?' then for goodness sake, try it! You won't break the ZX81 and you'll probably learn something. "

I found this book informative and easy to follow. I am happy to recommend it to beginners.

Ronald H. Miller, Murrysville, PA

5

STAR HUNTER — 8K/1K

PIE CHART GRAPH AND DISPLAY — 8K/16K

In Star Hunter, you control a laser cannon that fires when you press "F". The cannon aims upward when you hit "D" and downward when you hit "CH. You may fire and move simultaneously.

Your ship is stationary on the left side of the screen as stars move towards you. The object is to shoot a star before one of them hits the left side of the screen. For every star you destroy, you are awarded 150 points. When you top 1500, a faster attack wave starts and your score resets to 0.

To exit, hit break and ENTER.

Robert L. Nappi , Ashtabula, OH

1 RRND

2 LET R=©

3 LET P=©

4 LET R=R-M

5 LET G$ = _ 88

1

10 LET R = 1I 23 LET B=©

30 LET O-INT CRND*2©} *1

31 LET U =0+5

3-4 IP O-H >U~R THEN GOTO 3©

4© GL5

41 PRINT RT ©,25;P

42 PRINT PT 0.; 10.; "hTThCK UftUE

50 PRINT RT R,B;

50 PRINT RT R+l .B; *•

T0 PRINT RT

50 IP INKEY$ = "D'S THEN LET R=R- 2© IP XNKEY$ = **e“ THEN LET RsR*

100 PRINT RT Q , U ;

110 LET y=y-R

iii^IF U<2 RND RB5 CR-O) <2 THEN

113 IP U<2 THEN GOTO 1©

120 IP XNKEY$ = **F*! THEN GOTO 150 14© GOTO 5©

15© PRINT RT R,B+3; R$

151 PRUSE 5

152 CL 5

130 IF R=D THEN GOTO &&&

1G0 GOTO 50

200 PRINT RT 0,U; “SHftSH*'

210 LET P=P+150

220 PRUSE 2©

221 IP P > 150© THEN GOTO 3 24© GOTO 1®

5YNTRCTIC SUM: 40552., SK ROM

If you have more than IK RAM, try adding Dan Tandberg's Blast Effects (Aug. 82) or Paul Quail's Screen Background (Jun.82) routines. — Ed.

This program draws a pie chart graph with up to 10 sections on 8K ROM, 16K RAM machines.

Enter Pie, then RUN. The com¬ puter asks for the number of cate¬ gories (segments) you want and then each category's name and value. Answer each question as it appears, pressing ENTER after each. The title is limited to 10 characters.

After your last entry, your ZX/TS draws the graph. It also lists the categories with their percentages of the total.

To copy the graph and listing on a printer, enter Y in response to the question printed at line 4. Line 947 determines whether to copy the screen; if your printer does not use the ZX/TS keyboard printer commands, modify line 947 to use your printer's command to copy the screen display.

Segment resolution is fairly good, down to 17% of the total.

To chart new data, RUN Pie again. It stops after each run.

Ron Oblander, Ann Arbor, MI

PRQGRRM TO O UP TO TEN C fi

OUTPUT DI

1 REM PIE

2 PRINT RT 2©*©;

RRU R PIE CHRRT FOR TEGORIES"

3 SCROLL

4 PRINT "IS PRINTED SIRED?"

5 SCROLL

PRINT “ENTER Y SH -

INRUT R$t

HHiNiT R$

SCROLL

PRINT "ENTER NUMBER OF

6 V

S'

IS

20

GORIE5 - "

CSTE

2 1 INPUT C

22 PRINT C

23 DIM ETC}

24 DIM C$(C,18)

25 FOR 0=1 tO C 2S SCROLL

27PRINt "ENTER TITi-E QF CRT EG

as INPUT

29 SCROLL

30 PRINT C$CD}

36 SCROLL

GORY ”?D^"--"^TER URL-UE CRTE

42 INPUT E CD!

43 SCROLL

44 PRINT EfDJ i9 NEXT D

o© LET T=0 55 FOR F =1 TO C

6

37 LET T =T +E ( F 5 53 NEXT F tjQ SCROLL

El PRINT "TOTRL RMQUNT IS “;T 62 SCROLL S3 SCROLL

Si PRINT “PRESS ENTER TO CONTI NUE"

65 INPUT B$

70 FOR G = 1 TO 22 75 SCROLL

« fTi WFVT ri

w w % ; *» % w

65 CCS

10© REH CIRCLE

103 PLOT 31.. 21

11© LET RRDS =2 1

12© FOR P=S TO 3© STEP 2

13© LET RRDisi=.S17453fP

14-0 LET R=SIN RRON^RRDS

150 LET B=COS RRDN *RRD5

IS© PLOT (31 +B5 .. (21*R5

170 PLOT (32 -B5 .. (21+R5

IS© PLOT (32-B) .. (21-R5

130 PLOT (SlfB) .. (21-R5

20© NEXT P

21© DIM S (05

215 DIM Z (05

22© FOR X=X TO C

23© LET S (X5 =E (X5 ,'*T

235 NEXT X

24-© FOR L=© TO RRDS

250 PLOT 31.. ( 2 1 -f L 5

263 NEXT L

270 FOR V = 1 TO C

2S© LET Z (Y 5 =S ( Y 5 *363 * . © 274-53

230 NEXT Y

4-0© DIM U(C5

4-03 LET U ( 15 =Z ( 15

4-05 FOR Y=2 TO C

4-1© LET U ( Y 5 =Z ( Y 5 *U ( Y - 1 5

4-2© NEXT Y

4-4-0 GOTO 80S

450 FOR Y=1 TO C-l

460 IF U(Y5>=© RND U(Y5<=«5 *PI THEN GOTO S5Q

47© IF U(Y5>.5*PI RND U(Y5 C=PI THEN GOTO SO©

4S© IF U(Y5>PX RND U (Y' 5 < = 1 . 5 *PI THEN GOTO 55©

50© LET U (Y 5 =2*PI -U (Y 5 510 FOR L=s© TO RRDS

52© PLOT 31-SIN U(Y5 *L,21f€OS W

(Y 5 *L

53© NEXT L

54© GOTO 683

550 LET U(Y5 =U(Y'5 -PI

5S3 FOR L =S i O RRDS

570 PLOT 31-SIN U (Y 5 *L , 21 -COS

CY'3 *L

5S© NEXT L 59© GOTO SS©

600 LET U (Y5 =PI-U (Y'5

61© FOR L=© TO RRDS

623 PLOT 31+SXN U(Y) *L.,2i-COS

U

(Y 5 *L

S3© NEXT L

640 GOTO 683

65© FOR L =0 TO RRDS

660 PLOT 31-t-S IN U (Y' 5 *L,2I *005 U

(Y'5 *L

67© NEXT L 680 NEXT Y 6S5 FOR Y s 1 TO C

63© IF U(Y'5>=© RND U(Y) < = .5*PI THEN GOTO 75©

635 IF U(Y5 > * 5 *PI RND U(Y5 <=PI THEN GOTO 735

70© IF U(Y'5>PX RND U(Y'5 ( = 1.5*PI THEN GOTO 72©

70S LET U IY 5=2 *P I -U ( Y 5

7 10 PR 2 NT RT 1 1 -COS U (Y 5 *10 . 15 - SIN U(Y'5*1©;Y'

715 GOTO 752 720 LET U (Y5 =U (Y'5 -PI 725 PRINT RT ll+COS U(Y5*1©. 15- SIN U(Y'5*1©;Y'

73© GOTO 752 735 LET U (Y 5 =PI-U (Y' 5 740 PRINT RT 11 fCQS U 1Y' 5 *10 . 15 * S XN U CY' 5 * 1© ; Y'

745 GOTO 752

75© PRINT RT 11-COS U (Y'5 *10.15* SIN U(Y'5*10.CY

752 NEXT Y

753 PRINT RT 11.15;“*“

755 GOTO 90©

600 REM MRRKING OF SEGMENTS

SI© DIM U(C5

62© LET U ( 15 =Z (15 /2

S3© FOR Y =2 TO C

64© LET U (Y'5 =Z (Y'5 ^2*U (Y-15

65© NEXT Y'

66© GOTO 45©

90© IF R$ = “Y'“ THEN COPY'

3©4 PRUSE 20©

9©5 CLS

9 1© PR INT “ CRTEGQRY' “ ; TfiB 14 ; “RM OUNT" TRB 23; “PERCENT"

915 PRINT

92© FOR Y=I TO C

925 PRINT Y' ; " » “ ; C $ (Y 5 ; TRB 15; E

(Y 5 ; TRB 22; S (Y' 5 *100 935 NEXT Y'

94© PRINT TRB 14;" - “

945 PRINT TRB 9; “TOTRL"; TRB 15; T

347 IF A$="Y'“ THEN COPY' q50 STOP

5YNTRCT XC SUM: 23272.. SKXlBH

We will pay

CASH

for non-exclusive rights to manufacture and sell your Timex/Sinclair educational and entertainment programs.

DALLAS DEVELOPMENT SYSTEMS 7410 Stillwater Garland, Texas 75042 (214) 238-1776

7

SOLAR PROGRAM FOR

FLAT PLATE COLLECTORS — 3K and up

If you're using solar techno¬ logy to reduce your energy bills, a computer can help maximize your benefits. SOL will help you orient that flat plate collector.

You need the following informa¬ tion: your latitude, vertical tilt

of the collector, and azimuth (de¬ viation from true south) — all in decimal degrees. You can adjust the tilt to receive minimum heat in summer or equalize the tilt (ver¬ tical); add 20 percent for months of snow cover. Because of screen limitations, hourly totals are not printed out. They are available while the program is running — 1(B). Changes made to run in the ZX81 cause slight inaccuracy, but the results are within 2% of those obtained with a larger computer.

SOL runs with 3K RAM and up.

If you omit the graph routine (lines 640-890) , it should run in 2K. The program takes about 3.5 minutes to run — it goes through the subroutine 132 times. The graph gives an easy-to-interpret picture of year-around performance. Remem¬ ber that the monthly figures are for one day only and that they assume no shade.

Ed Buttenhoff, Grand Rapids, MI

10 REM 'SuL 2© GOTO ©22©

3© REM SUBR TO CALC BTUS 4-0 FAST

5© LET 1=4.29* ( J + ( . 034#COS 0360

*N/365*F) > >

80 LET D =23 , 4-5+3IN 036©* C234.+M

> /365*F>

TO LET DaD*F

0S8®*COS hI>Tin l*sin °*tcos L*C i©0 JF M>94.„S76 THEN LET X=0

11© JF W<=94.976 THEN GOTO 0130 12© GOTO ©I4-©

130 LET X —EXP ( - ,

14-0 Lt ! V=tXP ( — « ©9t>*HJ 150 LET I = X * . 56 * ( X +Y }

ISO LET CaSIN D * \ SIH L+CGS T- (C OS L*5IN T 4- COS A> >

170 LET 0=04-005 D*COS HI* * COS L *005 T + (SIN L * S IN T * CO S .A j <

*SIN A*S

15© LET 0=0+005 D*SXN N HI 19© LET I = X*C 20© XF X-;© THEN LET I -O 21© RETURN 22© DIM X l 12)

23© DXM G ( 12)

24-0 LET U=1 25© LET K =2©

26© LET F=PI/i39 270 5 LOU

'" SOL AR ENERGY , BTU y S8F

230 PRINT T/DRY"

230 PRINT ^'r’TOR **

~300 PR XNT

'FOR FLAT PLAT COLL USE DECIMAL DEGREE

.—i

310

32©

4-20

4-3©

idf!

4-7©

480

PR XNT INPUT LL

330 PRINT .,/TXLT ANGLE?"

34.0 INPUT TT 350 PRINT , , "AZIMUTH?"

360 INPUT AA 37© LET L=LL*F 35© LET T-TT *F 39© LET A =AA *F 4-00 LET U=©

4-1© LET N =21

FOR 0=U TO 12 LET H =75 LET R=0

4-5® FOR B =G TO 11 4-60 LET HI =H *F GO SUB 004-0 LET X <&> =X 4.3© LET H=H— 15 50© LET P=P+I*S.*

51© NEXT B

52© LET N =N +30.36

53© LET G O = XNT VR+.E*

Fly LizT U=U+H 550 NEXT O 560 CL 5

570 PRINT TAB 1©; "SOLAR TABLE" ,

, , " LAT = ";LL; " T XLT = ";TT; "

A7 = " ’ A A

55© PRINT' , , " MONTH B

T U y D AY /SOFT "

59© PRINT

60© FOR I=U TO 12

61© PRINT TRB 5-LEN STR$ X; X; TR B 25-LEN STR$ Gfl.> ;6fl)

62© NEXT X

63© PRINT TOTAL V i DAYVMCU

= ” TAB K; XNT <U+.5>

6 4-0 PRINT , VFOR GRRPHtNJSE

** "CONT" "> "

65© POKE 164.15, U 660 STOP 670 SLOW

65© LET A$=" + - + **

69© FOR X=U TO K +U+U 70S PRINT R$

710 NEXT J

72© PRINT AT K U; " 5"; AT IS,U; ” 1©” ; AT 1©.,U; ”15”; AT 0 , U; ”25"

730 PRINT AT K,1S;"5";AT 15,15.; "IS"; AT 1© , 15; "15"; AT 5,15; "SO"} AT ©’, 15; "25"

8

74-0 FDR R=U TO 12

7S0 XF D VR) < 376 THEM GOTO 0770

7S0 PLOT R*2+5, ( (G (R) ) /S0) V

770 NEXT R

730 POKE 164-13 , U

790 PRINT RT U+U*K,©;"

UflSQND -{MONTH"

§00 PRINT RT © , K ; "SOLRR RRD"

P 10 PRINT RT J+J,K; " STU DRY " ; ftT 0,7; X 100

320 PRINT RT 4-,K;”PER 60 FT"

330 PRINT RT 6,K; "LftT = H:LL 34-0 PRINT RT 3,K; "TIL T = " ; TT 350 PRINT RT IO,K; "RZIH= " ; RR 860 PRINT RT 14- , K ; " i FOR TRBLE , " ; RT 16/K; "USE ""CONT""***

370 STOP 38© FR6T 890 GOTO 0660

5YMTRTIC SUM: 64-737 ; 3K ROM

DECIMAL-HEXADECIMAL CONVERSION PROGRAM — 8K/16K

This utility program converts values in decimal (base 10) from 0-65535 to hexadecimal (base 16) equivalents. It also takes hexa¬ decimal values from 0-FFFF and converts them to decimal equiva¬ lents. After entering the listing, simply RUN — prompts and error mes¬ sages will help you along. The program can also be listed on a printer. Decimal-Hex Conversion was developed by Softcrest, New Canaan, CT.

Gytis Adams Kevis, New Canaan, CT

	3—- ■> - ft. J. W V— • l*J	_ _ _ R* _
fT—a	£T h.* r*. SH l i	i ft j— r*. a a 5U
-> y	t % Ua. • ■ ■%* * W IF- « V W • ft	O m mm* m tk m m
o	REM REM	... CO r*. r% . . . 'wU
* \	REM	. . . BY
r 1.0	r-. T f-t W afta t 1	H$ { 15
Lr i«’i w w	D IM	R$ C4 >
W ft-X	r~v -r* a « w JL «”•	D $ (63
40	D IM	B (4-3
50	DIM	T (43
52	LET	T (1 > =
54	LET	T (2) =;
	et	• r — • ft W / —
V J-N	« •	-a— .* -f ft i » * -
	t r-~ t	\ ft f. __ rt 1“
W W % w	? t-* ft	3 = 133
*1 0 0	J""\ ill 5 J	R=23
i 13	FOR	0 = 1 T
120	LET	HS (C3
13©	LET	R=R + 1
^40 r* j— ft. « --ft ft,f»	HEX {— j ^	T C
w «w 150	W l^a W r% r*^. -r f -L	NT RT
.~v » ft % % \*ftft W %	.—ft \ t-ft r— • LrU'w'C.	ft

CONNECTICUT. . . 0034-3 COPYRIGHT, . 2. 362 . . . . BY. .G'rTIS. . RC-RrfS . . .

ITS PRINT RT 11,4-; “ I FOR DE

CIHRL TO HEX **

ITS PRINT RT 13. 14- ; “OR¬ IS© PRINT RT IS!. ©; " 2 - > FG

R HEX TO DECIHfiL ”

I3S INPUT P

2©S IF P=1 OR P-2 THEN GOTO 250 2 IS CLS

22© PRINT RT I©, 2; "RE-ENTER CON UER5IGM CODE"

23© PROSE 1©©

24-© CLS 2 5 © G OTO 1 S©

2S3 CLS

2TS GDSUB G jjp

253 PRINT RT 1 S , 2 , “ HOPE CONUERS

Ions v /n t **

29Q INPUT P$

3SS IF P$<>"N” THEN GOTO S©

313 CLS 323 STOP

1000 CL.S

1313 PRINT RT IB . 2 ; “ENTER DEC T?-?c

L vRLUE S -65535 " *

10-23 INPUT P

1333 LET Z=P

1332 IF P < >© THEN GOTO 1343 1334- LET R$ = ** 0”

1335 GOTO 1175

134.3 IF P>3 RND P (b5535 THEN GOT O 1133 1050 CLS

13 EG PRINT RT 13 .2; ** DEC IMRL URLU

E IN URL ID"

1373 PRINT RT 11.2; “ RE-ENTER B RGUMENT “

3S3	PROS	E 133
323	GO j O	1333
133	FOR	C = 4 TO	1 STEP
1 10	LET	X = I NT	iP/HCJ
123	LET	Y=X*HC
ICO	LET	R= i P -V	> *1
143	LET	R$ CC3 =	H$ (R)
.153	LET	Cr — V* % — * *.
ft . ft »% ft— r w	NEXT	ft * ft—*
i ^ ft xy	x- ft <— ft i * — ft » “ft « i nJ w w w	S 1223

11.-5 P'R I NT Pt 1,3;

***************"

lies PRINT RT 2,©;“*"; TRB 2; “ DE

CIHRL HEX IDEC IMRL * "

1193 PRINT RT 3.©;" *".TRB 27; "

1233 PRINT RT 4.3; “ *" ; TRB SlZ jTR

B 12;"=“; TRB i8.;R$;TRB 27;"*“ 1235 PRINT RT 5,©;”*************

*****************

121© RETURN 1223 FOR C=1 TO 4

123© IF -i :»"©** THEN GOTO 12E-

©

12-4-0 LET VC.* =" "

V* --"ft *■»-< „i ^ ft, • *•— % .« 1 ■■ ■ .«-k

a -w — % *.m im r» at i

lie© RETURN

»a *— "a . — • <■*' •• a

A Zl / \L' ^ !>**

’CL. 3

2© 1© FOR C = 1 TO 4- 2323 LET B fC) =3 2333 NEXT C

H©4© FRIHT RT 18- . 2 ; "ENTER HEX IC-E

C.IMBL Y4BLUS Q-FFFF '

205© INPUT D S

2352 LET D$ (S TO S)="

2354 GOSUB 2333

2353 GOSL&B 223©

237© FOR C = 1 TO 4

£©S© IF D$ iCJ = ” ** THEN GOTO 211©

2323 LET P=CODE D$ CCJ —2-3 213© LET B fC.i =P*T fC>

9

2110 NEXT C 212© LET R=©

213S FOR C-~S TO 4 214.0 LET R=R+S tCJ 2153 NEXT C 2 155 P P INT fiT i , @ > *****************

2I6S PRINT RT 2,0:”* “ ; TPS 2;** HE XIDECIHftL DEC IHRL *

2170 PRINT RT 3,0; 27.;"*"

2150 PRINT RT 4L,«; TWS s; D$; r

«e 15; trb is; r; tss 27; - *"

2185 PRINT RT 5..©; *************** *****************

2x33 RETURN 220S LET S = i

2210 FOR C-S TO 2 STEP -1

2220 IF 0$ V 4.V «>" " THEN COT O 222

3

225© LET E-S if ?'5*1/ TO 51 c'5 TO

C-2)

2240 LET D* CS» = ” "

2250 LET 5=5+1 2250 NEXT C 2233 RETURN 2300 LET E =0 2310 FOR C = 1 TO 4-

2315 IF D$ CCi = ” " THEN GOTO G3SU

2320 IF CODE £>$ tO 4 23 OR CODE Iv$ v C >’ >4.3 THEN LET E = 1 2330 NEXT C

2340 IF E=© THEN GOT O 2333 235© GOSUB 2480 2350 GOTO 2303 2399 RETURN 240© CL5

241© PRINT RT 10 .2; ** IMURLID CHRRRCTER CSi **

2420 PRINT RT 11,2: "CHECK RND RE -ENTER YOUR UflLUE **

2430 INPUT D$

2435 CLS

2440 LET D$C5 TO Si =**

245S RETURN

3VNTRCTIC SUM: 34.864. . 8K/1SK

MC PROGRAMMING #11: STORING MC SUBROUTINES IN REM

[All numbers in this article refer to the 4K ROM ZX80; for 8K ROM (ZX81/TS1000) , see "Machine Code Programs: Where and How to Load Them" in Syntax Quarterly, Winter 1982. — EO]

While you can store machine code subroutines anywhere in your BASIC program, the best place is 1 REM (& 2 REM, if you have two subroutines) .

The first address will always be 16427. The first BASIC program address is 16424 and holds 0 if the program line number is less than 256. The second address, 16425, will hold 1 for line 1. 16426 holds the code for REM, 254, and the

first subroutine address will thus be 16427.

Since subroutines use non¬ character code numbers, displaying MC bytes usually makes the ZX80 crash. 1 REM is the easiest line to keep off-screen since it is at the "top" of your program.

If you store your subroutine below other program lines, adding or editing program lines above it will change subroutine addresses.

Here is an easy method for entering MC subroutines:

1. Reserve some storage space for storing your machine code program. Enter "1 REM AAA" etc., including as many A's as bytes your subroutine requires. Any character will do; the idea is just to reserve addresses.

2. A buffer against listing line 1 is advisable, so enter 2 REM B.

(This will not protect against line 1 showing after hitting HOME or LIST, however.)

3. Now, or after entering the input loop, POKE 16403,2 to bump line 1 off-screen. This trick will also work if you accidently LIST and the screen is "skewed" but not "scrambled". Move the cursor down a few lines first, though.

4. Enter the input loop:

100 FOR X=16457 TO 16457+(xx-l)

110 INPUT Y 120 POKE X , Y 130 PRINT PEEK X,

140 NEXT X

Where xx is the number of bytes in your machine code.

5. GO TO 100 and enter your codes. Entering from a 4-column written table eases input checking.

6. SAVE on tape in case your subroutine crashes.

7. Enter LET Q=USR(16427) to test your subroutine for a crash. ("Q" can be any variable letter.)

8. Enter the rest of your BASIC program.

Next month: CALLING AND RETURNING Jon Bobst, Zeta Software, PO Box 3522, Greenville, SC 2608-3522

lO

SOFTWARE REVIEW

Product: ZX81 Home Computer

Package: Etch-A-Screen,

Music Composer, Checkbook Balancer, Billboard ROM/RAM required?: 8K/16K Printed Listings?: No Programs Listable?: No Easy to Load?: Yes Written in: Machine Code Display: Good

From: Lamo-Lem Laboratories, Box

2382, La Jolla CA 92038 Price: $9.95

Lamo-Lem's Home Computer Pac¬ kage of 4 machine code programs offer a good variety for a reason¬ able $9.95.

Billboard gives you a continu¬ ous left to right scrolling screen- size message. The message can be up to 250 characters and repeats until you enter a new one. You can even save your message on tape.

The graphic display is clear and steady and it's the kind of item that could be a visual enhancement at a convention or store window or for simple fun.

Etch-A-Screen lets you draw a picture anywhere in the top 17 screen rows. The pen moves in all directions including diagonally and holding down one of the designated graphic keys gives you continuous line movement. The directions to this program were hazy in sections. For example, it is unclear in the manual that to get the asterisk (the drawing pen) to appear, you must hold down one of the arrow keys while shifting. Also, the directions neglect to explain that you must press shift A to clear the title screen and then shift 9 (gra¬ phics mode) to actually draw. These problems are minor when stacked against the program's merits. Lamo-Lem includes a screen display sheet if you want to plot out your masterpiece before you start.

Music Composer lets you play 4 octaves on your computer. The

sound reproduces poorly through the TV, but is better through a radio. The directions are clear and straightforward and Lamo-Lem pro¬ vides you with a color keyboard overlay that translates ZX81 keys into octave keys, special effects keys and edit keys. A music com¬ position sheet is included for serious composers.

Checkbook Balancer tabulates your checking account and coordi¬ nates it with your monthly bank statement. It also comes with a keyboard overlay that assigns (+) , (-), CLEAR, VOID, ENTER and SAVE functions to keys on your ZX/TS.

Each program comes with notes for advanced programmers, making possible such extras as reprogram¬ ming Composer to play Sinclair's BASIC as if it were music. Refer¬ ence cards, which summarize program commands, are included for 3 pro¬ grams. The ZX81 Home Computer Pac¬ kage is a worthy set of programs for a good price. — PPW

PORTABLE COMPUTER POWER

Protect your Sinclair in o portable, dust free work station. 6xtra storage space for 6 tapes, connecting cables, power and ram pack.

Removable lid allows in-case operation.

Non-skid feet prevent desk top scratches.

Absolutely the most efficient and convenient way to protect, store, and transport your computer system.

Only $54.95 in continental U.S.A.

Dealer Inquiries LUelcome

CflS€S INC. P.O. Box 33820 Seattle, UJfl 98133 (206) 365-5210 VISA MAST6RCRRD

DEAR EDITOR

I have a couple of questions concerning Sinclair's Spectrum.

First, will SYNTAX cover the Spectrum and its associated hard¬ ware? If so, when will there be an in-depth review? How about a com¬ parison between the Spectrum and the VIC-20 or other comparable computers?

Also, what is the Spectrum's availability and price?

Russell L. Gagnon, Oscoda, MI

For more info see SYNTAX May 82 p.4, and Sept. 82 p.7. We will compare Spectrum to other low-cost color machines such as the VIC-20 and the TRS-Color in future issues of SYNTAX and SQ. We will expand our coverage on Spectrum when it becomes available; expect US intro¬ duction early 1983. UK pricing for the 16K version is 125, and goes to 175 for 48K. UK Spectrums work only with UK TVs. — KO

I am having difficulty getting my ZX81 to accept line 280 of an Annuity Program, Jun.82 p.17. It appears as follows:

280 LET N= (LN (R/(R-S*I) )/(LN(l+I) ) Please advise!

R.J. VanEstenberg , El Cajon, CA

LN is a function token meaning natural log; type it by pressing SHIFT ENTER to get the F function cursor, then pressing Z. — EO

I have a MicroAce with 4K ROM and 2K RAM. It runs well with the 4K ROM but when I put Sinclair's new 8K ROM in place it didn't work. The TV image was very distorted. I tried switching it on and off, pressing all the command keys, even changing ROMs, but the computer still remained distorted. Any suggestions?

Nivio Swami A. Valois, Brazil

We can't tell from your letter if you made the changes described in SYNTAX Apr. 81. You can't just unplug MicroAce's ROM and insert a Sinclair ROM — the pinouts differ slightly. Once modified for Sin¬ clair's 8K ROM, the socket only works directly with Sinclair's 4K ROM. — KO

Do you know any way that sound can be used with a Sinclair ZX81, via a recorder or any other method?

Carl Bush, Baltimore, MD

Generate cones in machine code by toggling bit 0 of A between execu¬ tions of OUT FF instructions.

Change frequency using time-eating loops. Listen with a speaker attached to the ear jack of your recorder, set up for SAVE. This method works only in FAST, perhaps why game manufacturers don't use it. Quicksilva offers a sound board accessory for £ 26.00 or about $45. You'll also need OS's mother¬ board, §L 12 or about $20. — EO

I recently came across a good deal on a batch of 4116 integrated circuits, which are 16Kxl dynamic memory chips. Can I build addi¬ tional random access memory for my ZX81 with these?

Patrick d'Entermont, NS, Canada

You can try to duplicate the 16K RAM pack, but only do it to gain the experience of building it — it's not a worthwhile project to save money. You'll spend many hours trying to duplicate their circuit. See Sinclair's 16K RAM schematic in SO, Winter 82. — KO

In machine code programs the "RST 28" instruction, (hex EF) which causes a jump to the float¬ ing arithmetic, is very valuable.

I am aware of how certain data codes following this instruction can be used to perform functions on

12

the stack. However while happily searching through the ROM (8K) for "RST 28" instructions, I came upon some data codes I was not aware of. For example, the code (hex) A0 was commonly used. SYNTAX readers would benefit from a list of these codes and their functions; a lot of aspiring machine code programmers don't even know about the wonderful "RST 28" instruction.

Referring to the above, I made sure that the (hex) EF's were not part of another instruction by checking for the exit code (34).

Joseph G. Kuzma, Jackson, MI

In 8K ROMs, floating point instruc¬ tions follow RST 28. The ROM rou¬ tine at 0028H interprets these, and they are explained in Ian Logan's ROM Disassembly Part B, available from Gladstone Electronics, 1585 Kenmore Ave., Buffalo, NY. — EO

Ross Shuping of Greenville, NC asked about a way to merge two or more programs (Sept. 82 p.12).

I first POKE one program above RAMTOP, thereby protecting it from being erased while you load the other program in. Then, POKE the protected program back into the display file immediately above the program that you just loaded. You can extend this procedure indefi¬ nitely, RAM space permitting.

Send me $2.00 and a SASE I will send a detailed explanation of this procedure to anyone who needs it.

Harold Miller, Rt. 2 Box 2330,

Clayton, GA 30525

It was interesting to note in SYNTAX the complete opposite of the problem I am encoutering — horizon¬ tal bars on the screen.

I, too, have the 9.75 VDC 650 ma power pack. Even with IK memo¬ ry, I still get the bar travelling up the screen; but, in my case, it gradually disappears the longer the unit is operating.

I opened the case and found four diodes with no designation on them. As Mr. Bosley intimated in SYNTAX Aug. 82, p.12, it could be one or two of the diodes.

Is there any way I can find out what the replacement value is for these diodes?

William Mitchell, Ontario, Canada Use lN4002s — KO

USERS' GROUPS

Here's our latest list of new ZX/TS users' groups. To check for a local group not listed, drop us a line (with a self-addressed stamped envelope) or call. We'll refer you to any group we know of. To list your group, write or call and we'll send interested people to you.

SYNTAX, RD 2 Box 457, Harvard MA, 01415, 617/456-3661.

Franklin County, VA: Gary Preston, c/o Irvin, Route 1, Box 21, Glade Hill, VA 24092.

Mechanicsburg, PA: Central PA ZX81 and TS1000 Users Group, G Antrim Dr., Mechanicsburg, PA 17055, 717/766-8365.

Montclair, NJ: North Jersey Tirnex- Sinclair Users Group, 133 Christo¬ pher St., Montclair, NJ 07042.

Monterey, CA : John Caylor, 698 Van Buren, Monterey, CA 93940, 408/372- 7988.

Nashua, NH: Nashua Area Radio Club, 11 Briand Dr., Nashua, NH 03063.

Send SASE for details.

Petaluma, CA: Personal Computer Services, Northern Calif. Sinclair Users Group, 129 Saratoga Ct., Petaluma, CA 94952.

Rockford, IL: Robert Cunningham, 1602 Midway Dr., Rockford IL 61103, 815/877-8106.

13

BEHIND EVERY GOOD SINCLAIR IS A MEMOPAK

If you own a Timex-Sinclair 1000 or ZX81 computer, you .should have a Memopak behind it. From increased memory to high resolution graphics, Memotech has a Memopak to boost your system’s capabilities. Every Memopak peripheral comes in a black anodised aluminum case and is designed to fit together in “piggy back” fashion to enable you to continue to add on and still keep an integrated system look.

^»»f

Printer Interface-^ Memopak RAM

High Resolution Graphics

Order at no risk

All Memotech products carry our 10 day money back guarantee. If you’re not completely satisfied, return it in ten days and we will give you a full refund.

And every Memotech product comes with a six month warranty. Should anything be defective with your Memopak, return it to us and we will repair or replace it free of charge. Dealer inquiries welcome. To order any Memotech product call our toll-free number 800/662-0949 or use the order coupon.

i'M'ivian

CORPORATION

7550 West Yale Avenue Denver, Colorado 80227 (303) 986-1516 TWX 910-320-2917

Mail to: Memotech Corporation, Code: STX-11

7550 West Yale Ave., Denver, CO 80227

•Price Qty. "Ibtal

1 64K RAM	$179-95
j 32K RAM	109 95
\| 16KRAM	5995
Centronics Parallel Printer Interface	104.95
j RS232 Printer Interface	13995
High Resolution Graphics	144.95
I Shipping and handling	4.95	$4.95 1
. * All prices quoted in U.S. dollars		Tkx**
• Colorado residents please add sales tax J □ Check □ MasterCard □ Visa		Total
Account No.		Exd.

Name
■ Address I
Citv L		State Zip 1

Memopak 64K RAM The 64K RAM extends the memory of your Sinclair by 56K to a full 64K. It is directly addressable, user transparent, is neither switched nor paged and accepts such basic command as 10 DIM A (9000). The Memopak 64K turns your Sinclair into a powerful computer suitable for business, recreational and educational use. No additional power supply is required.

Memopak 32K RAM The 32K RAM Memopak offers your Sinclair a full 32K of directly addressable RAM. Like the 64K Memopak, it is neither switched nor paged and enables you to execute sophisticated programs and store large data bases. It is also fully compatible with Sinclair’s or Memotech’s 16K RAM to give you a full 48K of RAM.

Memopak 16K RAM The Memopak l6K RAM provides an economical way to increase the capabilities of your Sinclair. And at the same time, it enables you to continue to add on other features with its “piggy back” connectors. It is compatible with the Sinclair 16K or a second Memopak 16K or Memopak 32K to give 32K or 48K of RAM respectively.

Memopak High Resolution Graphics The Memopak HRG contains a 2K EPROM monitor and is fully programmable for high resolution graphics. The HRG provides for up to 192 by 248 pixel resolution.

Memopak Printer Interface The memotech centronics parallel or RS232 printer interface paks enable your Sinclair to use a wide range of compatible printers (major manufacturers’ printers available through Memotech at significant savings). The resident software in the units gives the ASCII set of characters. Both Memopak printer interfaces provide lower case character capabilities. The RS232 Interface is also compatible with modems.

New products coming soon Memotech will soon be introducing four new Sinclair compatible products: a high quality, direct connection keyboard, a digitizing tablet, a 16K EPROM and a disk drive. Watch for our future advertisements.

HARDWARE PROJECT

This circuit will simplify loading and saving programs by eliminating ground loop noise without the need to pull out the earphone plug during saving and the microphone plug during loading. A separate switch resets.

Build this circuit with jacks on the input (power and cassette) side and plugs on the computer side. Use a small DPDT switch for the cassette switch and a normally closed pushbutton switch on the "hot" (tip) side of the power supply circuit. Use a 12V pilot lamp (Radio Shack 272-332) and coaxial cables. Be careful to keep connections tip to tip and ring to ring; mistakes here can be serious.

To save a program, throw your switch so that MIC connects; to load, use the other position.

Reset with the pushbutton.

Martin Albrecht, Oakland, CA

APPLICATION. ..FINANCIAL.. .EDUCATION...

K MARKET CALCULATOR 16K

I Astronomer’s Guide - Two diverse programs geared for Hangman - An educational game featuring; build your Calculates all types of stock investments and options [both the amateur and professional. Includes Astromap own library, competitions and five pre-recorded spelling Designed by an experienced stock market executive, land Conversions. drills.

MORE TS1000/ZX81 SOFTWARE FROM

SOFTSYNC, IIVC.

14 East 34th St. New York, N.Y. 10016

(212) 685-2080'

M/C & VISA ACCEPTED

WRITE FOR FREE CATALOG & PROGRAM LISTING

15

64K MEMORY

M-64 $119.9k?t	BYTE-BACK Co. m-64
129.95 WIRED & TESTED
IN STOCK. SAME DAY SHIPMENT
All standard features included, plus lower 8K of RAM can be disabled in 2K segments to allow PROM or peripherals to be added.

EXPAND YOUR 16K SYSTEM

95

If you have a Sinclair 16K RAM module and need more memory, expand it to 32K and beyond by usinq BYTE-BACK M-16 MEMORY MODULES.

You can’t connect two Sinclair 16K RAM modules together, but you can connect one Sinclair 16 K and one or more BYTE- BACK 16K modules to get all the memory you need

THOUSANDS IN USE WITH PROVEN RELIABILITY

M-16 $59 •95 Kit. $69.95 wired and tested.

IN STOCK. SAME DAY SHIPMENT

BB-1 Control Module, with 8 relays, 8 leds

& 8 inputs. $59 Kit. $69 wire and tested. IN STOCK! SAME DAY SHIPMENT

MODEM with RS232 Port. $99.!

$1 19.95 wire & tested.

90-Day Warranty On All Modules. 10-Day Return Priviledge ORDER PHONE 803-532-5812

Add $4.95 shipping & handling to all orders.

CHECKS

BYTE-BACK CO.

Rt. 3 Box 147 Brodie Rd. LEESVILLE, SOUTH CAROLINA 29070 *■

HARDWARE REVIEW

Product :

From:

Price :

Computer Keyboards Professional Keyboard Kit and Enclosure for ZX81 Dean Electronics LTD. Ascot Birkshire, England Gladstone Electronics 1585 Kenmore Ave.

Buffalo , NY 14217 716/874-5510 Keyboard Kit $119.95 Enclosure $29.95

To get full use of this key¬ board, I strongly suggest the extra investment for the enclosure. It allows the ZX/TS printed circuit board (PCB) to be housed in the same unit with the keyboard.

Keys are marked with Sinclair legends, and the keytops are remov¬ able. There are also six extra keys for any future use. The kit comes with complete instructions for removing the ZX/TS PCB and remounting it in the enclosure. It

also details connecting the PCB to the keyboard. Two ribbon cables are provided for this purpose. The completed unit is an attractive black aluminum case with a sloped front and clear, easy-to-read keys. There's plenty of room for adding extra circuits.

Assembly would have only taken about 45 minutes if not for several unforeseen difficulties.

Allowances were made in the enclosure for the I/O port (for printer and RAM pack) and the side connectors of the ZX81. These enclosures were designed for the British ZX81, not the U.S. counter¬ part. The result: three needed modifications. First, after remov¬ ing the ZX's PCB, I removed the small metal tab that grounds the inside aluminized plastic case of the ZX to the PCB. It's not neces¬ sary to the computer's function and is there to allow the ZX81 to pass FCC regulations. In the enclosure it could interfere with keyboard operation.

Next, the small switch on the PCB used to select the VHF TV chan¬ nel (also not on the British ver¬ sion) must be moved — it does not clear the bottom of the enclosure chassis. Simply unsolder the switch and resolder it sideways.

Finally, the hole provided for the video modulator output (or TV socket) is about 1 1/2" too close to the front of the enclosure. The easiest solution is to drill a new hole in the enclosure, wide enough to allow the modulator plug and socket to clear the enclosure case. I had to drill through the bottom chassis of the enclosure as well. Don't allow metals outside the plug or socket to make contact with the enclosure .

Despite the extra work in¬ volved, the ease and joy of using a full sized keyboard, without the worry of typos, outweighs the need to make minor modifications.

Jim Moyer, Ontario, Canada

16

BOOLEAN DEMONSTRATION — 8K/1K

If the ZX81 is your first exposure to computers and program¬ ming, you may have trouble under¬ standing Boolean logic. Initially, I was completely confused by the explanations and exercises for the AND, OR and NOT functions as pro¬ vided in ZX81 Basic Programming. A friend showed me a program similar to Listing 1, and I began to com¬ prehend the mysteries of Boolean algebra after running a few values for X and Y through it.

I dressed the program up a little and added a replay function. If you only have IK RAM, delete odd-numbered lines. One note of caution! Add a new line 175 STOP. This prevents error 7 (no corres¬ ponding GOSUB for a RETURN state¬ ment) in the shortened version.

To run the program hit RUN, ENTER. You are prompted to key in values for X and Y. The results of the AND, OR and NOT functions are displayed for you. The program prompts you with "AGAIN? (Y/N)".

To rerun, hit Y ENTER; N ENTER lets you exit the program.

Any numeric values can be used for X or Y, but zero and one can illustrate most of the salient points. Try the following values for X and Y:

X Y X Y

0

1

-1

0

-1

0

1

-1

1

-1

Were you surprised at the results? Go back and reread Chap¬ ter 10 of the ZX81 manual. The AND, OR and NOT functions can be

very useful and powerful program¬ ming tools!

John C. Connell, Middletown, RI

4-0 PRINT "ENTER A URLUE FOR Y .

78 IF X RND V THEN GOSUB 3©Q 3S IF X OR Y THEN GOSUB 4-00 00 IF NOT X THEN GOSUB 500 188 IF NOT Y THEN GOSUB 600 110 PRINT

12@ PRINT "THE URLUE OF X RND Y

■»— » ■ a .

w mm .»

it .

255 PRINT "AGAIN? (Y/Ni "

255 INPUT fi$

IS

C X AND Y 5

"THE URLUE OF X OR Y IX OR Y 'i

v W V

4.00 PRINT 41© PRINT 42© RETURN 5©© PRINT 51© PRINT 52© RETURN 60S PRINT 610 PRINT "NOT Y 52© RETURN 70S CLS 7 15 GOTO 1© i ass r« c.

1315 PRINT "THE END" SYNTRCTXC SUM : 35677

THEN GOTO 705 AND Y UAS TRUE . " OR Y UAS TRUE . " NOT X UAS TRUE . "

URS TRUE . "

SK / IK

r

i®

HEAR THE POWER OF YOUR

SINCLAIR

It’s been said that the future belongs to those who under¬ stand computers. If that’s true, what better way to do this than by having them talk to you.

Now you can. Quickly. Simply. Economically.

Let the power of your Sinclair ZX80/81 ™ or Timex Sinclair 1000™ speak for you now. Through R.I.S.T. Computer Components, Inc. CHATTERBOX™ — your ZX80/81 or TS1000 can speak. ..clearly, concisely and without limit.

R.I.S.T. has developed a state of the art voice synthesis module you plug in. CHATTERBOX utilizes allophone concatenation to synthesize speech, with limitless vocabulary. Sentences, and any English language word can be created. /

Best of all, CHATTERBOX is affordable. For $69.95, your ZX80/81 or TS1000 can give you the t/oice of the future... today!

R.I.S.T. Computer Components, Inc.

P.O. BOX 499 , Ft. Hamilton Station, Brooklyn, NY 112090499

My computer is □ ZX80* □ ZX81 □ TS 1000

Enclosed is $ _ for _ module(s) at $69.95 ea., plus

$3.00 Shpg ea. (includes complete documentation).

□ *9V Power Supply (optional) $9.95 ea. (Required for ZX80 or expanded system operation).

For orders outside continental U.S., please send bank draft.

i

NAME.

ADDRESS CITY _

STATE

APT. ZIP _

17

HARDWARE REVIEW

Product: MD-1 Direct-Connect Modem

and RS-232 Port From: Byte-Back Co., Rt. 3,

Box 147, Brodie Rd., Leesville , SC 29070 (803) 532-5812 Price: $99.95 Kit,

$119.95 Assembled

Some people just aren't happy with the limited world of the 8K ROM ZX81. Perhaps they shouldn't be. Ads tell you that information awaits you at your fingertips. The tool you need to access this infor¬ mation is a modem.

Modem stands for modulator- demodulator, because it converts electronic signals into tones that can travel over phone lines. Typi¬ cally, modems either connect dir¬ ectly to the phone line (called direct-connect) , or connect to a telephone handset through a speaker near the mouthpiece and a micro¬ phone near the earpiece (called acoustically coupled).

Input to a modem consists of a serial bit stream (the number of bits per second sent to the modem is called the baud rate). Modems don't care what bits you send them, but they do care what voltages you use to represent 1 and 0. Most modems use the RS-232C standard.

But even RS-232C doesn't specify the code used to represent differ¬ ent characters.

Most computers (ZX/TS ex¬ cluded) use the American Standard Code for Information Interchange (referred to as ASCII) internally, and therefore communicate with modems and terminals using ASCII. Since ZX/TS machines do not use ASCII, software or hardware must translate or you will only be able to communicate with a limited sub¬ set of computers.

One final definition: modems use different frequencies to trans¬ mit than they do to receive. Ob¬ viously, one modem must transmit on

one set of frequencies while the modem at the other end receives at those frequencies. The frequencies used by the modem at the calling end are the originate frequencies? the others are called the answer frequencies. Modems that can use either set are called originate and answer modems. Many modems used by personal computers originate only.

Byte-Back's MD-1 incorporates a board to generate RS-232 signals, a direct-connect, originate and answer modem board to generate standard communication tones, and cassette software to translate ZX/TS code into ASCII and vice- versa. You needn't worry about not being able to call up your favorite computer system with a MD-1 — you can communicate with virtually any kind of computer using the MD-1 with your ZX/TS computer.

We did not build the kit, but the instructions seem complete and clear. Byte-Back also provides technical assistance by phone.

Without modifications, the software provided with the MD-1 runs 300-baud ASCII through the modem, sending uppercase and con¬ trol characters only, and receiving uppercase and lowercase (lowercase characters are displayed in reverse field). My first attempt at using the modem failed because the compu¬ ter I called insisted on lowercase input. For speed, the software had to be written in machine code (listing available for $10), and requires modification to act as more than a "dumb" terminal. Byte- Back plans to offer software allow¬ ing downloading programs from Com¬ puServe (a database system) and storing data in memory. On the other hand, the software provided fits nicely in 2K RAM (but not in IK), dispensing with the need to carry a RAM pack with you to use your TS1000 as a portable terminal. Carrying a recorder to load the tape is a greater drawback.

Byte-Back's hardware exempli¬ fies good design: careful choice

18

CLASSIFIED ADS

of components to minimize cost; quality, neatly laid-out circuit board; simple packaging; low cost. Their software, on the other hand, works with no frills, and, in fact, with not all the neccessities.

Most of the missing features (no lowercase input, for example) can be avoided easily. But if you expect performance like a typical $1000 terminal, there is no emula¬ tion of cursor positioning, clear screen, home, or many of the other amenities that have been in term¬ inals for years.

If you don't mind loading a program to use your modem, and don't need frills (or can add them yourself), Byte-Back's MD-1 will work for you. — EO

Reach thousands of ZX80/81, TS1000 owners! Send your ad, typed 35 characters/line (including spaces and punctuation) , with check or money order for $9/line. Include your telephone number, whether or not the number appears in ad copy. Ad must arrive by the 15th of any month for the next month's issue. Any ad arriving after the 15th will appear in the issue following the next unless you request its return. Ads must be resubmitted for each month. No phone orders or credit cards. We take no responsiblity for advertisers or products advertised. SYNTAX Classified Ads, RD 2 Box 457, Harvard, MA 01451

TWO NUMBERS IN ONE BYTE — 8K/16K

Suppose you have a large program, lots of data, and not enough memory. Is there any way to fit more in less?

If your integer data always falls in the range 0 to 15, you can store two numbers in each byte (character) of a string array (since there are 256 different character codes) by multiplying the first number by 16 and adding it to the second. In the accompanying program, line 70 stores two numbers (N1 and N2) in the Xth character of a string, and lines 120 and 130 read them back.

Rolf L. Miller, Ventura, CA

***********************************

* SOFTWARE for ZX81 and TS1000 *

* Games , Business , Utility and more *

* Send $1 for air new catalog *

* refunded with first order, to *

* GREAT LAKES SOFTWARE, 2 01 Burl- *

* ington Rd, Valparaiso IN 46383 *

***********************************

*ZX80/81 Owners New Filter Network* *Cures your interference problems * *Fully tested w/60 day warranty. * *A11 parts UL-CSA approved. *

* ONLY $49.95 plus $4 shipping. *

*(VT,add 4%Tx) Send check or MO to*

* DYNAMIC CONCEPTS, INC. *

*6 Eaton Ave. Springf ield ,VT. 05156*

TRANSPARENT DUST COVERS to fit your ZX81/TS+16K $3.49 ea.:MIKE ROBERTS 1367 E. 12th, Des Moines, la 50316

IS DIM a £ C 3 j_

gw t- ytj V = 3_ i Q rj

o©	PR IN	T N2
70 v—. .-•v J— V,	LET^ NEXT	fi $ ( X ) =CHR$ *. /	* f .T .. .» j— . •> .— V X iwi xb twc: ?
W 0 *1. 0 0	-"v 4— k -r“ a W ■ IV* z a -- t S—\. — t T *. t K K JL r-4	• » "T
110	FOR	X = 1 TO 5
x£S	L_cE i	Nl= INT (CODE	f X i /16J
13©	LET	N2=COC-E Ri	(X)	— i HI IS )
24-0	PR IN	IT HI . M2
153	NEXT	V

SYNTACTIC SUM; 224-SB, SKy'i&K

***f or TIMEX/SINCLAIR computers***

LOST IN SPACE (uses SLOW) - 11.95

UNIVERSAL INVENTORY FILE - 16.95

UNIVERSAL MAILING LIST - 10.95

UNIVERSAL COIN COLLECTION - 10.95

UNIVERSAL STAMP COLLECTION - 10.95

UNIVERSAL COMIC BOOK COLLECT.-10.95 UNIVERSAL BASEBALL CARD COLL.-10.95 UNIVERSAL RECORD ALBUM COLL. — 10.95 Each program on cassette + manual.

( 8K R0M,16K RAM) M.C.Hoffman Co. P.0. Box 117, Oakland, NJ 07436

19

SYNTAX offers a faster way to find answers! Laminated Microprocessor Instant Ref. Cards Z80, 6502, 8080A & 8085A, 8048 & relatives and programmers' algorithms ref. card, $5.95 ea. Prices include shipping.

** "EPHEMERIS V" (C) PLANET FINDER** Any date, time, place on Earth — Finds RA&dec,constell, azimuth&alt for the major planets, Sun&Moon! Plus LOCAL sidereal time, moon phase&much more! 16K For amazing cassette send $8.00 to:EPHEMERIS V 124 Professional Ave **P0 Box 261 Winchester, Ky 40391**

FIND GOLD IN CALIF-16K TAPE $3. Free-Sf twr &Hrdwr Cat. -No Tape over $3-R0SE 269 DAHLIA I.B.CA. 93032

** ADD MEMORY THAT WON'T FORGET! ** * Kit $31:90 SASE details: HUNTER * *1630 Forest Hills OKEMOS MI 48864*

EDIT, DELETE AND " WITHOUT SHIFTING on big keyboards. Schematic: $4.95 SI/TI 25 Hilltop Ave, Lex MA 02173

FINANCIAL PLANNING TAPE-Annuities , Mortgages and more-for ZX81 $9.95 SIMEX 25 Hilltop Ave, Lex MA 02173

MC LINE RENUMBERER (DOES GOTO&GOSUB) Utilities $5 (SASE for info) TO Brown SOFTWARE 53 CLIFF LANE LEV. NY 11756

ZX81 VIDEO MONITOR AMP. COMPOSITE Output. Installs Easily Inside Case, Instructions Included $9.95? JDC 5-14- SENTINEL RD. ? DOWNS. ONT. CANADA

PUT YOUR TIMEX/SINCLAIR COMPUTER TO WORK! Maximize your investment with the TIMEX/SINCLAIR SOURCEBOOK which list programs, hardware and books for TS and ZX computers. $6.95+1.25 P&H TX res add $.35. MDC Dept SY-11 PO Box 280 Carrollton, TX 75006

***********************************

* CUSTOM ATTACHE CASE Formfit for *

*ZX80/81,TS 1000 and hardware for *

*inf o send SASE COMPUTA-DEK 6009 *

*Kenwood Dr. Nashville, Tn. 37215 * ***********************************

DRY GULCH. An interactive adventure written in the classic style. Over 100 words of vocabulary. This one will take days to solve. Written in BASIC, it is listable and may be SAVEd in progress. 8K/16K. Send $10 for a cassette to: UPSTATE LABS 27 ELVIRA STREET ROCHESTER, NY 14606

5 programs on tape 99 Free Details. Original Programs ,3763 W. Crocus dr. Phx,AZ 85023 Stamp Appreciated

*SLOTMACHINE*16K-LIST-$3 . 00 . 32K/64K’ Tape-$5.00.L.Youngberg, 13794 Beach Blvd , #433 , Westminster ,CA 92683

COMPUSETTE is a C-10 cassette which is especially designed for micro¬ computer application by TAPEMASTERS 25 for $20.00 100 for $70.00

VISA MASTERCARD C.O.D.

TX 214-349-0081**OTHER 800-527-1227 10% Discount for Check with Order P.0. Bopx 38651*Dallas , Texas 75238 FREIGHT PREPAID*DEFECTIVES REPLACED

*** THE DEFINITIVE TAX PROGRAM *** Fr 16K ZX81/TS1 000. EASY DATA ENTRY AUTOMATIC TAX COMPUTATION FOR EACH CHANGE, INCLUDING INCOME AVERAGING. Info:SASE, Cassette :10. 95. ** LQP

2365 Newcastle , Cardiff ,Ca, 92007 **

**NEW SPORTS PROGRAMS FOR ZX82 16K* FOOTBALL-Predicts which pro teams will win with amazing accuracy GOLF-Shows a hole by hole anylisis of your scores to improve your game BOWLING-Anylisis of score by frames Each program: Tapes $7 Listings $3 BRONZE STAR SOFTWARE PO BOX 265, Chicago Ridge,, IL 60415

***********************************

THE ORIGINAL AND MOST POPULAR!!! THE SINCLIAR COMPUTER FAMILY SOURCE BOOK (1st Revision) gives detailed listings of over 600 programs, books

6 accessories. 99 pg. only $6.95 + $1.25 P&H. VA res. add 4%. Send check or money order to ATLANTIC COMPUTER PRODUCTS, POB 936 Norfolk, VA 23501

***********************************

20

PROBLEMS? We deal in SOLUTIONS. Our professional quality hard/software are a step beyond the rest. Send an SASE now for a free catalogue to: PHOENIX ENGINEERING SYSTEMS , 704 Washington, Grosse Pte., MI 48230

$$$FALL SALE ON 16K '81 SOFTWARE$$$ ZX-FORTH, ZX-CALC (Spreadsheet) , ZX- FILE, Zx-BUDGET, ZX-PLAN(Per sonal Calendar), ZX-INVENTORY. $15 ea. or 3 for $40 or all 6 for $80. SofTek, Box 4232, Santa Fe, NM 87502-4232.

10 MATH UTILITY PROGRAMS :problem- solvers for teachers/students:Quad- r at ics , deter minents , series , statist¬ ics, etc. $7. 50 cass.THE RANCH SCHOOL Rt. 1 Box 150, Laneville ,Tx. 75667

IMPROVED HEATSINK eliminates over¬ heating of ZX81/TS1000 4 info:SASE B.Sanzone 289 Baxter La. Milford, CT

BUFFERED BUS KIT$63 ,BARE BOARD $43. UHF MODULATOR rids video noise $15. RIBBON CONNECTORS male , female , $8ea. Project Book $8. Opcode Program $4 COMPUTER CONTINUUM 301-16th Ave.

San Francisco CA. 94118 .( 415) 7526294

ZX81/TS1000 - 16K FINANCE SYSTEM.

Consists of 5 programs: Annuities, IRA Accounts, Trend Analysis, Compound Interest, Annuity Due. Menu driven, on screen update. $19.95 + $1 P/H. K & K Software, PO Box 6403, Falls Church, VA 22046

KROK — AN INTELLIGENT GAME AT A thinking man's price. 500 coins are scattered randomly in a 135-room maze in an ancient Mayan pyramid, differently each time of course. Bats, snakes, monkey sare a few of the graphic obstacles confronting you — but the greatest is KROK, the relentless pursuing crocodile. Maps, keys, magic rings, a sword open new doors, including doors in your mind. High quality cassette.

16 K RAM required. Satisfaction or refund. $6.95 from Brown Cottage Industries, 4386 Bright Hawk Court, Columbia, Md. , 21045.

Easy build portable table top cab¬ inet holds Timex/Sinclair , recorder , TV, wires and more neatly.Plans 2.50 Gabriel 108 Evans , Tiverton ,RI-02878

CHECKBOOK 16K Written in BASIC 200-400 checks and more $10 tape or info SASE to D Lipinski, 2737 Susquehanna Rd, Roslyn, Pa 19001

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ $ No-Limit DRAW POKER $

$ Challenge any 5 of 10 opponents $ $ - each plays differently - $

$ ZX81 16K Cass _ ZXP11C. . $16 . 95 $

$ TS1000 16K Cass. .TSP11C. .$16.95 $

$ $

$ BASICALLY SOFTWARE COMPANY $

$ PO Box 2987, Syracuse, NY 13220 $

$ Postage & Handling . $1.50 $

$ NY residents add 7% sales tax $

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

PAKGUY :Avoid goblins & gobble dots. SKYMINES:Move to destroy mines with lasers. 2 fast thrillers on cassette with 16K M.C! -$6.MILL RESEARCH 2307 Adanac St.Abbotsford,B.C.CAN. V2S4T1

***********************************

AT LAST: REVERSE VIDEO FOR THE ZX81 WHITE LETTERS ON A BLACK BACKGROUND FITS INSIDE CASE-ONLY 4 CONNECTIONS send check or money order $15.

SIGHT AND SOUND ELECTRONICS 1120 Bailey Hill Rd. #10

Eugene, OR. 97402 ***********************************

***FREE XMAS GIFT FOR ZX/TS USERS. Send printed stamped & self add¬ ressed envelope to:YAGSEE,POB 155 , VICKSBURG , MICH , 49097*************

LEARN DATA HANDLING-ZX DATE FINDER: for 16K ZX81s. A versatile file storage tool w/comprehensive file search, display and edit functions. 1900 words of data capacity. $9.95 gets you list/complete explanation or send for free specs and catalog. Tom Woods box 64 Jefferson, NH 03583

SALE-2K RAM-ZX81. WRITE D.F. ROBERTS 2138 Salamanca, Port Richey, FL 33568

21

ZX PROFESSIONAL PROGRAMMING FORMS 9xll-ea line, col, pixel numbered Pad of 50:1.99/5 at 9.25(25 post) pTp,7760 N. Hopdown , TucsonAZ 85741

WOW IK Games on Cassette: JUST $9.00 AUTO RACER, MINI ARTIST, DEPTH CHARGE BLACKJACK, eight more! Send to: H&H Electronics, 3 37 9 Rt46-6D,Parsippany NJ , 07054-P&H 75f-"FREE CAT." SASE ! !

*********** C.R.C. INC. ***********

* 16K PRACTICAL SOFTWARE FOR THE *

* HOME, SASE FOR FREE CAT&PR LIST *

* 2901 Auburn Auburn Hgts Mi 48057*

**ASTROLOGY 16K-Now you can write a comple t e, prof ess ional horoscope. All planets/interpretation.$17.L&S , POB 935 NewPaltz, NY, 12561 (914)255-5521

<*VOTEM*> Analog Interface* Measure voltage & temperature with your ZX* $39.95/kit-$59.95/asm-$5/doc alone* Add $3/USpost* Down East Computers* PO Box 3096 , Greenville ,NC 27834 * *6116 RAM 1K->2K w/soc $9.95 p.p. *

PLAY "T.V. FUED" ON YOUR ZX MACHINE Like the famous T.V. game show Requires 8K ROM and 16K RAM-Specify ZX80 or 81 version-on cassette tape $6.95 plus $1.50 shipping & handle DESERT SOFTWARE 212-B North Fifth Kingman, Arizona 86401

Put your ZX81 to work! Stock pkg. incl. Stk-Calc & Stk-File, or Bud¬ get Planner. Either: $5.95 cass. 3.00 Xerox to — Mike Putira 5 Farm¬ stead Lane, Rockville CT 06066.

INPUT AT Add this powerful command to your ZX81/TS1000. Equivalent to PRINT AT, it allows you to input va¬ riables from any location on the screen. Simply enter into REM's. Ex: 300 LET K=USR Input-At 310 REM INPUT AT 5, 2, A, V, AT 6,4 C$ Resides above RAMTOP(400 bytes). Pro vided w/ screen editor (uses * f) for simple data entry.Excellent for setting up menus. $12 Send check or MO to ANDES INT'L 219 S. MILITARY Rd Apt B SLIDELL, LA 70458.

EZRA GROUP II EZRA GROUP II

LOW LOW LOW LOW LOW LOW LOW LOW LOW

PRICES!

Biorhythms 8K ROM/lK&up . 1.00

Graphics Billboard 8/lup.. . 1.00

Horse Race 8/lup . 2.00

Plotting Work Sheet 8/1 . 3.95

Plotting Work Sheet 8/16 . 6.95

SPINNER TM ( like Rubik's) 8/16. ..2. 00

Improved SLOW PAUSE . 1.00

Linear Regression 8/lup . 2.00

CHEWTER TM (like Pacmn) SLOW/lup. 2 . 95

Dog Race 8/lup . 1.95

Random MUSICISLOW/1 up . 2.00

TAP WRITER TM (Handicap Aid) 8/1. free CHAR. Generator Demos 8/lup. . . . 2 . 95 ORDER or $1 refundable gets you GOODIES Catalog and !FREE! Program EZRA GROUP II EZRA GROUP II

POB 5222 San Diego California 92105

RELIABLE PROGRAM LOADING AT LAST!

ZX LOADMASTER unit does it right. For info send SASE to CINEVISION PO Box 546 Montebello Ca 90640

New game! "LOST IN SPACE" Moving graphics. Flicker-free. Steer ship past meteors & enemy ships. Land on fuel ship for bonus. Status fuel monitor $ current score. Auto-run. Prompts & more! for TS1000 or ZX81. 16KRAM. Cassette + Instruct. $11.95 (dealers wanted) M.C. Hoffman Co. P.0. Box 117, Oakland, NJ 07436

******* **CHAS. E. GILL CO.********* * * * * *f0RMERLY THE FUNWARE CO.****** l.LAND THE SPACE SHUTTLE 2. LAND/AIR BATTLE 3. SPACE BATTLE 4.HUNTMAN*ALL ZX-81/16KRAM ON QUALITY C-20 TAPES. EACH GAME $4.95 OR ALL FOUR $16.95. PAPER FOR ZX/PRINTER $6.50 PER ROLL ALL PRICES INCLUDE SHIPPING/HANDLE. 7119 Santa Fe Av. Dallas, Tx. 75223

HAVING PROBLEMS LOADING FROM TAPE? AI-1, auto level set, self contained interface corrects those problems for any tape recorder or deck. $25.00 pp USA. Send check or MO to: JACYN Electronics, PO Box 570, Port Orchard, WA, 98366

22

SOLVE LOADING PROBLEMS — DIRECT COPY ANY ZX/TS CASSETTE w. multi-feature WINKY BOARD 1 Easy to use. No mods. Free info. $18PPD,$12kit. G. Russell RD 1 Box 539 Centre Hall PA 16828

"SUPER DUNGON" This adventure game changes ea. time you play it. $20 ($5 charge on all returns) 8K/16K CUSTOM COMPUTERS 20927 124 Ave. SE Kent, WA 98031 (NO CODs, enc. pay)

OUR POLICY ON CONTRIBUTED MATERIAL

SYNTAX invites you to express opinions related to any Sinclair computer or peripheral, or the newsletter. We will print, as space allows, letters discussing items of general interest. Of course, we reserve the right to edit letters to a suitable length and to refuse publication of any material.

We welcome program listings for all levels of expertise and written in either Sinclair BASIC or Z80 machine code. Programs can be for any fun or useful purpose. We will test run each one before publishing it, but we will not debug programs; please send only workable listings. Programs submitted on cassette can be tested more quickly and with less chance of error.

In return for your listing, we will pay you a token fee of $2.00 per program we use. This payment gives us the nonexclusive right to use that program in any form, world-wide. This means you can still use it, sell it, or give it away, and so can we.

We will consider submissions of news and hardware or software reviews. Please keep articles short (350-400 words). Again, we reserve the right to edit accepted articles to a suitable length. We will pay 7 cents per 6 characters, including spaces and punctuation, for accepted articles.

When you send in programs for possible publication in SYNTAX, please include the following information:

• How to operate the program, including what to input if it does not contain prompts.

• Whether you can run the program over again and how.

• How to exit the program.

• The Syntactic Sum (program published in Feb. 81 and Jun. 81; send SASE for a free copy).

• What RAM size program requires.

• What ROM program uses.

We pay for this explanatory text at the same rate as for articles in addition to payment for the program itself.

If you want us to return your original program listing or article, please include a self-addressed, stamped envelope. Otherwise, we cannot return submitted material.

ZX ADVENTURE II — Latest "CASTLES & CREATURES" (TM) adventure game from CINQUEDA SOFTWARE. Challenging and enjoyable for beginner and advanced. 16K RAM. Complete instr. & tape. Send$9.95 chk or MO to: CINQUEDEA SOFTWARE 214 Indian Creek Drive, Pekin, II 61554

EZ-HEX Read-write-test Z80 machine code on your 16k ZX81. Count-move- convert between hex&decimal-even saves and loads above ramtop-all from menu. No more poking around. Z-WRYTER Word processor. Write and save text using powerful editing functions usually found on larger machines. $9.95 each on cassette- RCO Technical PO BOX 773 St Ann MO 630747

Programs for T/S 1000-Send $1.00 for catalog and game: BARLOG S/W 401 N. GEYER; KIRKWOOD, MO 63122

ZX81 2K UPGRADE-$14 FOR KIT- $24+ZX & I Will Upgrade. Micro Basics, 5768 ALBANS CIRCLE, LITHONIA, GA 30058.

FROG-IT! for IK ZX81!! Jump on moving blocks. Miss & die! Listing $2.50. PANERO SOFTWARE, 3309 Lewis, Long Beach, Ca. 90807. Ribbit!!

SYNTAX is published

monthly by a wholly-owned subsidiary of The Harvard Group.

Syntax ZX80, Inc.

RD 2, Box 457, Harvard, MA 01451.

Telephone 617/456-3661.

12 issues, $29. Single issue, $4.

Publisher: Kirtland H. Olson Editor: Ann L. Zevnik Assistant Editor: Pamela Petrakos-

Wilson

Editorial Assistant: Pamela K. Vinal Tech. Consultant: Eric Olson

YES! Please send me 12 issues of SYNTAX for $29.

□ My check for $29 is enclosed. □ Please charge my □ MasterCard Make checks payable to: □ Diner’s Club □ American Express

SYNTAX ZX80, INC. □ VISA □ Carte Blanche account

account number _ — -

exp. date _

signature _

Name _

Organization _

Address _

City _

Day PhoneJ _ ) _

I own a □ Sinclair ZX80

bank number (MC only)

Title

_ State _ Zip _ _

_ Evening Phone_i _ l -

U*St

□ Sinclair ZX81 Telephone orders call

617-456-3661

23

SYNTAX

12"B&W video monitor only $89.95. Includes free plans and kit of all parts needed to add a direct video output to your ZX81/TS1000. Direct video conversion kit alone is $9.95 Delux version $18.95f provides switch selectable normalor inverted video. Add $8.50- shipping&insur ance for each monitor , $1.50 for each kit Random Access, Box41770S,PHX AZ85080

SINCLAIR ZX81 TIMER MODULE!

3 CHANNEL, 5 MODE, TO 18 HOURS.

2 AMP CONTACTS . Software Control. Interval, Delayed Interval, On-Off

Repeat. $55 Lee Sorrell 3 Bahia CIRCLE, LAND O' LAKES FL. 33539

ZX81 ASSEMBLER in Basic & m.c. (12K) stand. Z80, hex/decimal constants, outputs anywhere. ZX81 DISASSEMBLER also Basic & m.c. (4K) , hex or dec. output. Both for $15.00 ppd. SERIAL PRINTER interface (thru MIC port) cheap & easy plans/listing $5.00 INTEGER BASIC COMPILER avail. Dec. 22 Keywords, 11 functions $22. Bob Berch 19 Jaques Rochester NY 14620

** DIRECTORY ** NAME S/ADDR/ ZIP/TELE Add/Del/ Seek/ Sort/Auto-Sav+Run/More Listable*16K*Tape*ZX81/TS1000 5 $9.95 NBB, 14 JORDAN RD, BREWSTER, NY 10509

***********************************

Speed it up! Your programming that is! Non-Trivial Solutions' ZXPRESS Integer Basic Compiler compiles ZX- 81 source code to machine language. This means your programs can be de¬ bugged rapidly in ZX-81 BASIC, then compiled. The compiled codes are stored in REM statements or in 2000H to 3FFFH address segment, if available. The ZXPRESS Compiler will make your ZX-81 20 to 50 times faster. It's variables are 16 bit two's complement integers. The com piler allows multiple statements/ line. With the ZXPRESS, the source code can be located anywhere and the position of the compiled code can be selected, allowing you to write a long program, compile it in pieces, then assemble the pieces. The ZXPRESS is available from N-TS for only $29.95. For mind stimu¬ lating recreation, N-TS continues to offer the games Letter Raiders and Life with Palette for $9.95 each. NON-TRIVIAL SOLUTIONS, P.0. Box 2941, Amarillo, TX 79105, 806/

379-5723. Check, MC, Visa welcome. ***********************************

$-WIN CASH PRIZES in ZX WORDGAMES-$ Info: SASE Box 505, Carmel CA 93921

24

Tl-E

H\RV\RD

GROLP

Bolton Road. Harvard, Mass. 01451

First Class

U.S. Postage PAID

Harvard, MA Permit No. 8 01451

MR WILLIAM TOMLINSON 58 68

3635 RIVERED6E DR.

JACKSONVILLE FL 32211