The Amiga 1000 parallel port uses a male DB-25P connector, whereas all later Amiga models (A500, A2000, A3000) use a female DB-25S. Beyond the gender difference, three signal positions are swapped: Ground, +5V, and /RESET occupy different pin numbers between the two generations. This adapter cable corrects those differences so that standard Amiga parallel peripherals can be connected to an A1000. The pinout assignments are documented in Appendix E of the Amiga Hardware Reference Manual; connecting a later-model cable directly to an A1000 without adaptation risks damage, since +5V appears on pin 23 of the A1000 but GND appears on pin 23 of the A500 and later.
25 PIN D-SUB FEMALE to the Amiga 1000
25 PIN D-SUB FEMALE to the Amiga peripheral
| A1000 | Amiga | |
|---|---|---|
| Ground | 14 | 23 |
| Ground | 15 | 24 |
| Ground | 16 | 25 |
| +5V | 23 | 14 |
| n/c | 24 | 15 |
| Reset | 25 | 16 |
All other straight over, 1 to 1, 2 to 2…
Notes
- The A1000 parallel port uses a male DB-25P connector; the A500, A2000, and A3000 use a female DB-25S.
- On the A1000, pin 23 carries +5V and pins 14–22 are GND; on later models pin 14 carries +5V (pullup), pin 16 is /RESET*, and pins 17–25 are GND.
- Directly connecting an A500/A2000/A3000 peripheral to an A1000 without this adapter risks applying +5V to a line expected to be GND.
- Pins 2–9 (Data 0–7), pin 1 (/DRDY*), and pin 10 (/ACK*) are straight-through and carry the standard Amiga parallel data and handshake signals on both connector generations.
Signals
- /DRDY* — Data ready strobe (pin 1, output); driven by the CIA-A /PC signal after a write to CIA-A Port B.
- Data 0–7 — Bidirectional 8-bit data bus (pins 2–9); driven by CIA-A Port B at address $BFE001.
- /ACK* — Acknowledge input (pin 10); triggers a CIA-A interrupt on falling edge (connected to CIA-A /FLAG).
- BUSY — Busy signal (pin 11, I/O).
- POUT — Paper-out signal (pin 12, I/O).
- SEL — Select signal (pin 13, I/O).
- Ground — Signal ground (A1000: pins 14–22; A500/A2000/A3000: pins 17–25).
- +5V — +5 V supply (A1000: pin 23; A500/A2000/A3000: pin 14 pullup).
- n/c — Not connected (A1000: pin 24; A500/A2000/A3000: pin 15).
- /RESET* — System reset line (A1000: pin 25; A500/A2000/A3000: pin 16).
References
- Amiga Hardware Reference Manual, 3rd Edition — Commodore-Amiga Inc., 1991 (parallel port Chapter 8 p. 259; connector specifications Appendix E p. 317)