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As readers of this column are aware, Computer Shopper has long been one of the biggest supporters of the Sinclair computer community. This section in the magazine is just one of the ways in which we have assisted, now there is another.
Delphi is an on-line service available to the computing public by modem and, among other services, offers Special Interest Groups (SIGs) where people can gather and share information. Computer Shopper has established such a group as an adjunct to the printed page. You are all invited to sign on and join Stan Veit and the other writers for Computer Shopper (including myself) in our new meeting place, C*SIX (Computer Shopper Information Exchange).
What will you find on C*SIX? First you can join in on one of the many Sinclair conversations you will find in the Classic Computers topic of the forum. Anything you have on your mind can be aired here, amongst your fellow Sinclair users. Any important information that I receive will be listed here first—months before it could possibly appear here in print! The database will contain a number of programs for each of our computers which can be downloaded for your use. Of course, we hope that you will share your public domain programs with us as well.
Of course, the most exciting feature of C*SIX has to be the conference area where we can get together and have a real time conversation with other members of C*SIX. Check the conference schedule in the SIG for the times and dates of regular scheduled conferences, or hold one of your own.
If you are not a member of Delphi yet it is simple to sign on with a special deal. For $19.95 you receive a permanent membership in Delphi, a command card, a 400 page manual and a 1 hour usage credit. (If you decide that Delphi is not for you, you may cancel your membership within 30 days and your membership fee will be returned.) Delphi allows 300/1200/2400 baud with no surcharge for high speed transmission.
To sign on directly:
- —Dial 617-576-0862 (At 2400 baud call 576-2981).
- —When you have carrier press Return once or twice.
- —Follow sign on instructions.
Via Tymnet:
- —Dial your local Tymnet number (To find that number call 800-336-0149).
- —When Please Type Terminal Identifier or a line of xs appear. Type A.
- —When Please Log In appears, type DELPHI.
- Follow sign on instructions.
Via Telenet:
- Dial your local Telenet number (To find that number call 800-336-0437).
- When you connect press Return twice.
- When TERMINAL = appears press Return.
- When @ appears type C DELPHI followed by a Return.
- Follow sign on instructions
Sign on instruction:
- —At USERNAME type SHOPPER and press Return.
- —You will be prompted for the information needed to establish your Delphi membership and set your billing account.
To sign up by VOICE line call Delphi at 800-544-4005, or in Massachusetts call 617-491-3393, or write to: Delphi Member Services, 3 Blackstone Street, Cambridge, MA 02139.
NOTE: The $19.95 deal is ONLY available for on-line sign-on. Regular rate is $49.95.
Hope to see you there soon!
On this note, we have a look at an incredible feat of programming for the ZX-81 family of computers. ZX-TERM*80 is a complete communications package for the ZX-81 (T/S 1000/T/S 1500) computer. It requires either the Westridge TS2050 modem or the Byte Back MD-2 modem. Two things make this program different from any other prior communications program for these computers. ZX-TERM*80 allows a full spectrum (sorry, no pun intended) of uploading and downloading facilities. You can send virtually anything which can be stored in your computer. ZX-TERM*80 is the first ZX-81 program which uses the Xmodem protocol, which has become the most popular transfer protocol and is supported by virtually all on-line systems, including private BBSs.
The main difference between this program and others is the display. Unlike older programs which only had a 32 column display, ZX-TERM*80 allows the user to select 40, 60 or even an 80 column display. Since most online services cannot transmit in 32 column displays, the ability to change the display will eliminate the split display which are such a problem on the ZX-81. In addition, ZX-TERM *80 allows the use—and display—of upper and lowercase characters as well as all the remaining ASCII and Sinclair characters.
ZX-TERM*80 requires that you have at least 16K RAM added (even if you have a T/S 1500) and either the aforementioned 300 baud Westridge or Byte Back modem. In addition you will need 8K static RAM mapped in the non-system 8K-16K region. Those of you with the classic Hunter NVM board can use it with a small modification. If you do not have a Hunter board (which is no longer in production) Silicon Mountain Computers sells a SCRAM board which will run this program (as well as Silicon Mountain Computers other hi-res programs) with no modification. You can utilize a full 64K with a plug in adapter available from Silicon Mountain Computers.
Your choice of printers makes no difference to ZX-TERM*80, as it will work with just about any printer imaginable. If you have a T/S 2040 printer (or Alphacom 32) you can copy the contents of any window at any time, or dump data to it after you have captured it. For full size printer owners, suitable print drivers are supplied. You can print directly to your printer as data is sent or received, or take the printer off-line and have the program continue as if no printer were attached.
Using ZX-TERM*80 requires a bit of setting up when it is run for the first time. You are asked questions such as which modem you are using, your printer type and your configuration. The default for this last is standard Xmodem parameters—8 bits, no parity and 1 stop bit. You will be given the opportunity to relocate the machine code and to indicate how much memory you will have at your disposal. Once the initial questions are asked you are given the opportunity to save this configuration for future use.
Once ZX-TERM *80 is transferred to its runtime position in memory you get to the main portion of the program. The default setup is a three window/40 column mode. The small window at the top will present you with all of your prompts and menus. Initially it will display, “DIAL NOW.” Two larger windows will appear below the first. The middle window (window (#2), which will display the ID legends at the beginning, will be used for your typed output. The bottom window (window #3) is where the data received from the remote computer will appear. The very bottom line is used as an auxiliary prompt line. This will display such information as the mode cursor which may indicate letter mode, symbol mode or control mode; a reminder that you can return to the previous level of ZX-TERM*80 by pressing Shift/Space (the equivalent of ESCape); a reminder that a shifted Enter will enter the symbol mode and the status of the buffer (open/close).
ZX-TERM*80 makes use of the WRX16 Hi-res core which we spoke about a few months back while discussing other hi-resolution programs for the ZX-81 family of computers. It is this routine which enables ZX-TERM*80 to accomplish many of its display features. Earlier telecommunications software were limited by the Sinclair low resolution (32 column) display. By using the WRX16 routine, Fred Nachbaur (author of ZXTERM*80) has redesigned three new character sets, 40 column, 60 column and 80 column. It is true, however, that the characters in 80 column mode are a bit on the compressed side and take a little while in getting used to. Imagine letters compressed and then placed so close to each other that not a single pixel exists between them. This is how the 80 character display is designed. However, if you are calling a system which is set for 80 column display (especially if graphics are used) this might still be easier to read than the split lines which occur using a shorter line length. More information is given in the appendix sections dealing with the dis¬ play. If you want, and are capable, you may even redefine these characters yourself.
In addition to both upper and lowercase letters, using the hi-res routine allows the definition (and use) of additional ASCII characters which would not normally be found on the ZX-81. These characters (such as ! & I # and many others) are accessed by first pressing the Shift and Enter keys. Since these are not on the keyboard itself, you may want to keep a printed list of the keys required to produce the desired characters.
Most on-line systems require the use of Control codes for the most effective operation. As you have noticed by now, the ZX-81 does not have the required Control key, as most other computers have, so ZXTERM*80 uses the Shift-3 combination to produce these codes. Codes sent are echoed to window #3 (except for the J [line feed] or ^ M [linefeed]).
You are given a number of options concerning the display of this program. You are given the ability to adjust the size of windows number 2 and 3 if desired. This is good to know if you need a larger area for typing messages, or want to allow the most area possible for incoming data. You can even go from a 3 window display to a single window display. The single window display is the one most used to display other programs. You don’t have your input and output separated, but you do get to see your communication in the proper sequence. In single window mode, though, you do not get the prompts which usually appear in window 1. You should either wait until you are familiar with the commands, or make sure that you have a “cheat sheet” by your side. In either case a simple Shift-7 will take you to the Display Options menu, from where you can return to 3 window operation. When uploading or down¬ loading files you will automatically be put into 3 window mode and returned to the single window—if that was your previous orientation. Conversely, when you choose to “View Data,” you will be placed in the 1 window mode for that operation.
As mentioned before, you also have the option of selecting a 40 character, 60 character or 80 character display. Beware that if you choose the 80 column mode and are dealing in numbers that you might get terribly confused since there are no spaces between characters in this format. Normal text is surprisingly easy to get used to quickly. You may work with the ASCII codes (32-127) as well as Sinclair’s own graphics. You may also select either normal or inverse video modes.
Finally, you have the option of either half or full duplex, as defined by echo on or echo off. Some remote computers will automatically echo back your transmitted characters, others will not. Because of this you will have to determine whether a particular service requires you to display what you send or not. This will soon become obvious to you. If you are showing double characters when typing, you need to turn your echo off. If you are displaying nothing that you type, turn it on.
In View Data mode you have the opportunity to examine what is in memory— including the program itself. You have a choice to examine this data either in ASCII or CLIVE CODE format. You may look at either a program or its variables if they exist.
File transfers these days rely on some method of error checking in order to see that the data is properly received. The most common of these methods is Xmodem protocol. Xmodem (sometimes called the Christensen protocol after the gentleman who developed it) claims a 99 + % reliability factor. This system transfers 128K blocks followed by a checksum. If the checksum transmitted by the receiving computer is correct, the next block is sent. If the checksums do not correspond the block is resent. ZXTERM*80 uses Xmodem to both upload and download files. (There is a newer version of Xmodem called Cyclic Redundancy Check—this is not supported by ZX-TERM*80.) The Xmodem feature of this program was written by Harvey Taylor. ZX-TERM*80 can upload a program and/or its variables.
As with any program you purchase, the documentation that comes with it can be just as important as the software itself. ZX-TERM*80 comes with a user’s guide that is 38 pages long. Many things about the program are included which will help the more knowledgeable user to further modify the program. The manual starts off with a “guided tour” which takes you step by step through the installation process as well as the first steps in getting on-line with another computer. Following the guided tour are sections which detail the program options more fully, and end with a summary of the functions (and the related keystrokes; discussed in that chapter.
For the technically minded there is a wealth of technical data on how the program was put together and how it works. For those of you who have the technical knowledge and understanding, this information may be put to use in many ways. Although the program is written for the Westridge or Byte Back modems, a little technical knowledge of any other modem you might have may enable you to modify the program to work with the modem. ZX-TERM*80 contains an auto-repeat which will continue to print a character as long as the key is held down. A POKE is included in the documentation which allows you to alter the speed of that auto-repeat making it faster or slower. The keyboard sensitivity (debounce) is quite high initially in this software and you may have to adjust it to your own preference. A POKE for this is included as well. These are just a few of the useful POKES given in the manual. For the true hacker (in the positive sense—not the one which means illegally breaking into restricted systems!) the appendices are full of useful information.
Once again Fred Nachbaur has come up with a remarkable program for the ZX-81 computer. For more information on ZX-TERM*80 and other programs and hardware for the ZX-81 write to: Silicon Mountain Computers, C-12, Mtn. Stn. Group Box, Nelson, BC VIL 5P1, Canada.
I want to thank all of you callers who have made Sinclair At Night BBS the success it now is, but want to remind everyone that it only operates from 11:00 PM through 6:00 AM Eastern time, 7 days a week. It can be reached at 718-627-1293.
Next month will be our fourth annual round-up column here in Computer Shopper. With the year end holidays coming up you will be sure to find just the right gift for that Sinclair computerist on your list so be sure you are back next month. See you all on Delphi and the C^SIX SIG!