The TRX-280 was a proposed motherboard replacement for the TRS‑80 Model 4, described in the December 1990 issue of Computer News 80 and issue 38 of TRSLINK. It was created by Peter Ray of Anitek Software Products in an attempt to design a “next generation” TRS‑80.
The TRX-280 design was based around the Z280, an enhanced Z80 compatible processor created by Zilog. The Z280 was an interesting chip, providing software compatibility with the Z80 yet adding many new features, such as a memory management unit, new addressing modes, and new instructions. It was also faster than the Z80 at the same clock speed.
The TRX-280 was planned as a drop-in replacement for the Model 4 motherboard (and possibly the Model III as well). It would have remained compatible with all TRS‑80 software and hardware, with the one exception that it would have lacked a cassette port.
The TRX-280 had an impressive set of proposed features:
- a Z280 processor running at 10 MHz (equivalent in speed to a 15 MHz Z80)
- 1 MB of memory, expandable to 4 or 16 MB
- a clock/calendar with battery backup
- a hard disk adapter with the ability to boot from a hard drive
- a floppy disk controller compatible with all types of drives (180K, 360K, 1.2 MB, and 1.44 MB)
- high resolution graphics compatible with the Micro-Labs Grafyx Solution
- text screen attributes, including underline, italic, bold, and expanded text
- an IBM PC compatible character set which could be mixed with ordinary TRS‑80 characters
- one or possibly two IBM PC compatible slots to accept standard expansion cards
The price of the TRX-280 was projected to be between $700 and $900.
There was a great deal of interest in the TRX-280, and there were already plans for new software to support it. The LeScript word processor, also by Anitek, was one product that definitely would have supported the new features.
Unfortunately, Zilog encountered many problems producing the Z280 and those problems were never completely resolved. Development of the TRX-280 ended before it could go much further than the planning stages.