Building a SYM-1 Expansion Board to Play the Very First Star Trek Game

Before the modern user-friendly aluminum slab laptops of today, and the generic beige PCs of the ‘90s, and the wonderfully-quirky 8-bit home computers of the ‘80s, the only way most people could get their hands on a computer for their homes was to build a kit. One of the most popular of those kits was the MOS Technology KIM-1 computer, which is hardly even recognizable as a computer like we think of them today. That was soon followed by a near-clone called the SYM-1 designed by Ray Holt and built by Synertek Systems. Bob Alexander has a vintage SYM-1 computer and built this expansion board for it in order to play the very first Star Trek video game.

The SYM-1, like the KIM-1 that it closely copied, didn’t have any features to identify it as a computer by modern standards. It had no keyboard or monitor — it didn’t even come with an enclosure or case. It just looks like a printed circuit board waiting to be put into some kind of electronic device. But it was a functional computer. Users could input commands and text through a small hexadecimal keypad, and outputs were shown in hexadecimal on a small six-digit seven-segment display. Even with such limited hardware, users could write programs in BASIC (and other languages) and then run them. An RS232 serial interface was available to connect a separate terminal or teletype machine.

Alexander wanted to use his SYM-1 to play Mike Mayfield’s 1971 text game, Star Trek. To do so — at least without having to enter the code himself or use a modern computer to send it via the serial connection — he built an expansion board. That board plugs into the bottom of the SYM-1, and contains 32kB of RAM, 32kB of ROM (with BASIC, an assembler, and a DOS), and, most importantly, a Commodore 1541 disk drive emulator from The Future Was 8 Bit. That disk drive emulator lets users load up a modern SD card with disk images and then send them to the computer.

In this case, the emulator works with a special SYM-1 version of a DOS (Disk Operating System) and is sending the Star Trek code to the SYM-1. Alexander still needed a way to actually play the game, and decided to use a DECwriter Correspondent hard-copy terminal for that. The DECwriter Correspondent is similar to my own Texas Instruments Silent 700, and features a keyboard for sending commands to the computer and a dot-matrix printer to create a hard copy of those commands and the resulting response outputs. As you can see at the end of the video, Alexander was able to successfully play Star Trek with that — and the proof is printed out permanently on the roll of paper.