I/O Map
The following table lists the main I/O definitions of the TMC-600.
| Q | Cassette Out |
| EF1 | Display / Non display period |
| EF2 | Cassette In |
| EF3 | Key press indication |
| OUT 3 | Keyboard latch |
| OUT 4 |
Printer output When using expansion ROM 1: Select AD/I channel 0 - E Select printer out with F, following OUT 4 will be printer output |
| OUT 5 | VIS (Video Interface System) data output to selected register |
| OUT 6 | When using expansion ROM 2: Disk I/O |
| OUT 7 |
VIS Register select:
2: Colour latch 3 - 7: 1870 OUT 3 to 7 |
| INP 4 | AD/I Input (channel 0 to E), only valid when using expansion ROM 1 |