Since this is a column in a British magazine, written by an American author about an American computer with British roots (follow that?), it is only proper that we devote this month's column to a comparison of the ZX Spectrum, and the American version known as the Timex/Sinclair 2068.
Quicksilva (who have an office here in Texas), and Melbourne House have made Spectrum software available already, and Richard Shepherd Software (who have supplied me with many excellent titles for review in my U.S. column) should follow soon. There seems to be hope for us yet!
While Timex's modem was finally released by the third party manufacturer who was to produce it for Timex, the biggest disappointment has been the lack of microdrives. Many of us originally purchased our T/S 2068's because of the promise of microdrives. A few disk drive interfaces are in the works (as are other goodies), but still we wait.
As always, I look forward to your INPUT, and welcome any comments, tips, or what have you.
The first and most noticeable change, is in the case and keyboard of the T/S 2068. The original T/S 2000 was in the black case with rubber "chicklet" style keys. While this was an improvement over the T/S 1000 (ZX-81), Timex changed the dimensions of the case to 14½" * 7½" * 1". The case now became silver/grey, and contained a hinged door at the right top which would be used for cartridge based software. (More about this later.) The keys were replaced by a full size keyboard with 42 solid plastic, soft touch keys, including a full size space bar. (One drawback to this keyboard is that the space bar seems to be "dead" on the ends, and must be hit close to the centre.) The sides now contained Atari standard joystick ports, which are supported by a new STICK command in BASIC. The final noticeable change is the addition of an on/off switch on the left side of the computer.
At first, Timex had planned on marketing two different versions - the 16K T/S 2016 ($149.95), and the 48K T/S 2048 ($199.95). Sound familiar? In the end, however, only the 48K model was released, dubbed the Timex/Sinclair 2068. Actually, it is in reality a 72K unit, containing a 24K ROM (16K + 8K bank switched to handle the cassette interface), and a 48K RAM. It is these ROM additions and changes that account for the incompatibilities that exist. As a rule, most software written in BASIC will LOAD and RUN properly, while machine code software will not. Additionally, the positioning of the individual bus lines in the edge connector are not in the same order as on the Spectrum, causing further, hardware incompatibility.
Changes to the Spectrum BASIC came about as well. In order to utilize the joystick ports, Timex added a command - STICK. This command reads the condition of the switches in the attached joystick. The form of the command would be as such;
The number 1 in the parenthesis defines either the button (1) or the stick (2). The second number refers to the left (1) or right (2) joystick. The T/S 2068 can read 9 different positions from the joystick. This opens up many possible uses of the joystick in a number of programs.
A second set of additions are error trapping features. These work with the ON ERR command. ON ERR GO TO xx placed into a program suppresses the error reports, and causes the program to jump to line xx when any error is encountered. ON ERR RESET causes the error reports to be reinstituted, and ON ERR CONTinue, causes the program to go back to the line where the error took place. These are very powerful commands to prevent a program from stopping when an error occurs, and can also be used to protect a program from being stopped (BREAK is considered an error) and listed.
The final addition to BASIC is an enhanced version of the BEEP command (which is also available on the T/S 2068), called appropriately enough - SOUND. The T/S 2068 has a three channel sound system, and each channel is controlled by fifteen registers. These registers control the pitch, duration, and volume of the sound being produced by that channel. You also have control of the envelope or shape of the sound. This means that using the SOUND command, and a lot of work, a T/S 2068 can play music in three part harmony. This command can also be used to produce a wide range of sound effects, and the manual illustrates gunshots, an explosion, and a whistling bomb. An interesting command, but very difficult to use. None of the programmers that I know (myself included) have been able to make much use of this facility. (There is one program named MUSICOLA which not only takes advantage of this capability, but allows the user the chance to compose music with harmony without understanding the SOUND command.)
Earlier we spoke about a hinged door on the top of the case which was to be used for cartridge based software. Timex had planned to release most of their software in two forms; cassette, and Command Cartridges. These Command Cartridges would utilize the "chip on a board" technology, whereby the IC would be attached directly to the board, eliminating the IC holder, and producing a very thin (just over 0.5 inch thick) wafer. This board would be encased in a 2.75 inch * 1 inch case to be inserted into the Command Cartridge port. When the computer is turned on, and senses the presence of a cartridge in this port, it automatically bank switches (the T/S 2068 contains bank switching architecture allowing the use of up to 16Mb!)to use (up to) an extra 56K.
However, as we here in North America are all too painfully aware, Timex withdrew from the computer marketplace before many of these Command Cartridges were produced, and since a great number of these cartridges must be ordered for production, no new Command Cartridges seem to be in the works from any supplier. Those of use who have a cartridge or two are fairly lucky. (I own two - States & Capitols, and Casino 1.)
This leads up to a current use of this port which is most encouraging for T/S 2068 owners. Since the majority of software for the Spectrum would not work on the T/S 2068, the introduction of a SPECTRUM EMULATOR was much anticipated and has finally become a reality. Originally developed by Timex during the development of the T/S 2068, I was shown one originally by Dan Ross (former Vice President of Timex) at a Timex Celebration in Boston. Had Timex continued with computers, this would have been marketed. When Timex backed off, the founder of a Timex users group in North Carolina made some contacts, did some research, and produced an emulator to be inserted into the Command Cartridge port, and introduce a pseudo Spectrum ROM. With this board in place, a T/S 2068 will run almost all of the software. Also available are chips which get placed inside the case (permanently) to give the same capabilities. One company developed a method whereby both the Sinclair and Timex ROMs coexist, and can be selected via a magnetic switch. (Note: The T/S 2068 is not made to be opened by the user as is the SPECTRUM, since no upgrades were available or planned. Americans in general seem to be less inclined to tinker than our British cousins.)