Model and ROM information
Information regarding Model type, PCB code, ROM marking, ROM version and checksum is captured here. S. Adolph
Note: I'll try to keep this list updated. If anyone has comments or corrections to this please let me know.
What Kind of Model 100 or Tandy 102 do You Have?
Model 100
The first M100s were released with a custom ROM pinout, in agreement with the published schematic. Over time, Radio Shack changed the design to use standard 27C256 compable ROMs. Both variants use essentially the same ROM code. Clearly the schematic for these later variants was different due to the ROM pinout.
Later, versions of the M100 were produced for UK and EU markets. These M100 appear to use 27C256 compatible ROMs, but the ROM code differs from the USA version. The schematic for these versions had changes as the UK M100 had no modem function, and the EU version had a different modem.
Tandy 102
Tandy introduced the 102 from the beginning using a 23C256 compatible ROM. There is a published schematic available. the T102 main ROM had a few improvements and bug fixes compared to the standard M100 main ROM.
Later, versions of the T102 were produced for UK and EU markets. The ROM code again differs from the USA version.
Model Type Information
You can tell these variants apart by observing the presence of the modem, and by looking at the PCB itself. The ROMs will have a unique marking, as does the PCB. In some cases the Tandy product number is different as well. This information is captured in the below table.
M100
Variant | Product number | PCB code | ROM marking | ROM checksum stock/y2k | ROM image | Note |
Early USA | 26-3801/3802 | PLX110CH1X | LH535618 | A2CC/A2D4 | m100 | This is the usual M100 |
Late USA | 26-(3801)/3802 | PLX110EH1X | 3256C07-3J1 | A2CC/A2D4 | same as above | Later version |
EU | 26-(3801)/3802 | ?? | 3256C05-3E1 | A8AF | M100rom-e_Y2K | Different modem |
UK | 26-(3801)/3802 | PLX120CH1X | 3256E30-4C3 | EEA4 | m100UK_nomodem | no modem, BCR, similar to KC-85 |
UK | 26-3801/3802 | PLX120BH1X | 3256E30-4F3 | ?? | ?? | no modem, BCR, similar to KC-85 |
UK | 26-3801/3802 | PLX120BH1X | 3256E30-3E1 | A8AF | same as above | no modem, BCR, similar to KC-85 |
T102
Variant | Product number | PCB code | ROM marking | ROM checksum stock/y2k | ROM image | Note |
USA | 26-3803 | PLX144FH1X | M53256-02 | A8CA/A8C2 | t102_rom | This is the usual T102 |
EU | 26-3803 | PPPCG2007A*01 | PB INT | B20F | T102_EU_modem | Different modem, QWERTY |
UK | 26-3803 | ?? | ?? | XXXX | binary file | no modem |