I/O Map
The following table lists the main I/O definitions of the Telmac 1800.
| Q |
- Sound on/off: fixed tone - Cassette out |
| EF1 | CDP 1861 display: display status |
| EF2 | Cassette In |
| EF3 | Keyboard pressed |
| OUT 2 | Key latch |
| OUT 4 | Address latch, after any OUT 4 RAM will be mapped at address @0000 instead of ROM |
| INP 1 | CDP 1861 display: display on |
| INP 4 | CDP 1861 display: display off |