Interactive Connector Diagram
Click or tap any pin in the diagram below to inspect its signal assignment, electrical specification, and wire colour standard.
Supported Systems / Found On — Retro Machine Hubs
This connector is used on the following retro computer systems. Click any colour-coded badge below to open its full board-level repair, diagnostic, and schematic Machine Hub:
Connector Specifications
Full Pin Assignment & Wiring Reference
| Pin | Signal Name | Direction | Electrical Spec / Role | Wire Colour / SCART / Adapter Target |
|---|---|---|---|---|
| DB25 Pin 1 | /STROBE (/DRDY) | Out | Active-Low Data Strobe pulse to Printer / Plipbox | Centronics Pin 1 |
| DB25 Pins 2–9 | D0 – D7 (8-Bit) | I/O | Pin 2=D0 (LSB) through Pin 9=D7 (MSB) — Bidirectional on Amiga CIA-B! | Centronics Pins 2–9 |
| DB25 Pin 10 | /ACK | In | Active-Low Acknowledge interrupt input (triggers CIA-B /FLAG on Amiga) | Centronics Pin 10 |
| DB25 Pin 11 | BUSY | In | Printer Busy status input | Centronics Pin 11 |
| DB25 Pin 12 & 13 | POUT (12) & SEL (13) | In | Paper Out (Pin 12) & Select Online (Pin 13) | Centronics Pins 12 & 13 |
| DB25 Pin 14 | AMIGA: +5V DC! | ST: NC | Pwr | Amiga A500/600/1200/2000/3000/4000: +5 V DC Pull-up Supply (powers Plipbox!) | Amiga: +5V DC |
| DB25 Pin 16 | /RESET (Amiga) | Out | Amiga System /RESET output | Centronics Pin 31 (/INIT) |
| DB25 Pins 17–25 | GND (0 V) | GND | Signal Ground Return (Pins 17–25 on A500+; Note: Pin 23=-5V, 25=+12V on A1000!) | Black (GND) |
Why the Amstrad CPC Printer Port Is 7-Bit Only (D0–D6)
On 16-bit machines (Amiga and Atari ST), the 25-pin D-Sub female (DB25F) parallel port matches the IBM PC Centronics standard on Pins 1–13 (Pin 1 = /STROBE, Pins 2–9 = D0–D7, Pin 10 = /ACK, Pin 11 = BUSY) — and on the Amiga it is fully bidirectional (driven by CIA-B 8520), powering modern Plipbox Ethernet adapters and stereo Covox samplers! On 8-bit British systems (BBC Micro, Oric-1/Atmos, Dragon 32/64), a 20-pin or 26-pin 0.1" IDC ribbon header is used with every even pin grounded.
- Amstrad CPC 464/6128 7-Bit Printer Quirk: To save a single flip-flop chip, Amstrad used a 74LS273 8-bit latch where 7 bits (D0–D6) drive the printer data lines and the 8th bit (D7) drives /STROBE! Standard 7-bit ASCII text prints normally, while 8-bit graphics use 7-pin ESC/P modes.
- Amiga Plipbox Ethernet & TechnoSound Sampler: Because Amiga DB25 Pin 14 provides +5 V DC directly on the parallel port, an Arduino/ENC28J60 Plipbox Ethernet adapter requires no external power cable on an A500/A600/A1200!