The E/RAM was a high-resolution add-on for the TRS‑80 Model I. Introduced in 1980 for a price of $349.95, the E/RAM was designed and manufactured by Keyline Computer Products from Tulsa, Oklahoma. It was sold by Vern Street Products, also in Tulsa.
The E/RAM (an acronym for Extended Random Access Memory) contained 6K of video memory. It increased the TRS‑80 graphics resolution to 256 by 192, with the high-resolution graphics overlaying the text screen. The graphics could be enabled and disabled using either software or a hardware switch.
The E/RAM came in a steel case measuring 2 1/2″ high, 6″ wide, and 12″ deep. The self-contained unit sat next to the Model I and installed in a straightforward way:
- The E/RAM plugged into an expansion card connector (on either the Model I or Expansion Interface).
- The Model I video monitor plugged into the E/RAM.
- The E/RAM and the Model I video plug were connected with a 3′ long video cable.
This meant that no hardware alterations to the Model I were required. The case also had an on/off switch, the graphics enable/disable switch, and an additional expansion card connector for any Model I hardware devices that required one.
The driver software for the E/RAM came on cassette, with nine high-resolution functions available. In addition to the software and hardware user’s manual, Keyline Computer products also offered a $15.00 E/RAM Hardware Service Manual “containing a theory of operation section, parts list, logic diagrams and schematics.” The manual also promised an E/RAM Systems Programmer’s Guide to be “available soon.”
The Vern Street Products advertisements disappeared in 1981, and the E/RAM was presumably discontinued at that time. In 1982, Keyline Computer Products introduced a $495 version of the E/RAM for the TRS‑80 Model II. According to a mention in Creative Computing, a version of the E/RAM for the Model III was considered, but never produced. The Model II E/RAM was discontinued soon after Radio Shack introduced their own Model II high-resolution product.