Interactive Connector Diagram
Click or tap any pin in the diagram below to inspect its signal assignment, electrical specification, and wire colour standard.
Click any pin to view its signal assignment, electrical spec, and wire colour.
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:
[Amiga Hub — Amiga (A500 / A600 / A1200)]
[Big-Box Amiga Hub — Big-Box Amiga (A1000–A4000)]
[Atari ST Hub — Atari ST (520ST / 1040STF / STE)]
[CPC 464 Hub — Amstrad CPC 464]
[CPC 6128 Hub — Amstrad CPC 6128]
[BBC Micro Hub — BBC Micro (Model B / Master 128)]
[Oric Hub — Tangerine Oric-1 & Atmos]
[Dragon 32/64 Hub — Dragon 32 & Dragon 64]
[MSX Hub — MSX (MSX1 / MSX2 / MSX2+ / Turbo R)]
[Osborne/Kaypro Hub — Osborne 1 & Kaypro II CP/M Luggables]
[Wasm Lab — .D64 Parser, 6502 Disassembler & ROM Patcher →]
Connector Specifications
Amiga DB25F (A500+)
Pin 1=/STROBE, Pins 2–9=D0–D7 (Bidirectional!), Pin 10=/ACK, Pin 11=BUSY, Pin 14=+5V DC!
Atari ST DB25F
Pin 1=/STROBE, Pins 2–9=D0–D7 (Driven by YM2149 Port B), Pin 11=BUSY, Pins 18–25=GND
Amstrad CPC 34-Pin Edge
7-Bit ONLY (Top Odd: Pin 1=/STROBE, Pins 3–15=D0–D6, Pin 17=NC, Pin 21=BUSY to 8255 PB6; Bottom Even Pins 2–34=GND)
Centronics 36-Pin Plug
Pin 1=/STROBE, Pins 2–8=D0–D6, Pin 9=D7 (GND/NC on CPC), Pin 10=/ACK, Pin 11=BUSY, Pins 19–30=Twisted-Pair GND
BBC / Oric / Dragon
26-Pin / 20-Pin IDC (Pin 1=/STROBE, Odd Pins 3–17=D0–D7, Even Pins=GND)
Full Pin Assignment & Wiring Reference
| Pin | Signal Name | Direction | Electrical Spec / Role | Wire Colour / SCART / Adapter Target |
|---|---|---|---|---|
| 1 | /STROBE (CPC Edge Pin 1) | Out | Active-Low Data Strobe pulse (Driven by IC108 74LS273 Bit 7 on Amstrad CPC!) | Centronics 36-Pin #1 / CPC Edge #1 |
| 2 | D0 (CPC Edge Pin 3) | I/O | Parallel Data Bit 0 (LSB — Bidirectional on Amiga; 74LS273 Q0 on CPC) | Centronics 36-Pin #2 / CPC Edge #3 |
| 3 | D1 (CPC Edge Pin 5) | I/O | Parallel Data Bit 1 (74LS273 Q1 on CPC) | Centronics 36-Pin #3 / CPC Edge #5 |
| 4 | D2 (CPC Edge Pin 7) | I/O | Parallel Data Bit 2 (74LS273 Q2 on CPC) | Centronics 36-Pin #4 / CPC Edge #7 |
| 5 | D3 (CPC Edge Pin 9) | I/O | Parallel Data Bit 3 (74LS273 Q3 on CPC) | Centronics 36-Pin #5 / CPC Edge #9 |
| 6 | D4 (CPC Edge Pin 11) | I/O | Parallel Data Bit 4 (74LS273 Q4 on CPC) | Centronics 36-Pin #6 / CPC Edge #11 |
| 7 | D5 (CPC Edge Pin 13) | I/O | Parallel Data Bit 5 (74LS273 Q5 on CPC) | Centronics 36-Pin #7 / CPC Edge #13 |
| 8 | D6 (CPC Edge Pin 15 — MSB) | I/O | Parallel Data Bit 6 (74LS273 Q6 — MSB on 7-bit Amstrad CPC 464/664!) | Centronics 36-Pin #8 / CPC Edge #15 |
| 9 | D7 (CPC Edge Pin 17 = NC!) | I/O | Parallel Data Bit 7 on Amiga/ST/PC (NC on CPC 464! Ground Centronics Pin 9 on CPC lead) | Centronics 36-Pin #9 (CPC: GND/NC) |
| 10 | /ACK | In | Active-Low Acknowledge interrupt input (triggers CIA-B /FLAG on Amiga) | Centronics 36-Pin #10 |
| 11 | BUSY (CPC Edge Pin 21) | In | Printer Busy status input (wired to 8255 PPI Port B Bit 6 on Amstrad CPC!) | Centronics 36-Pin #11 / CPC Edge #21 |
| 12 | POUT (Paper Out) | In | Paper Out status input | Centronics 36-Pin #12 |
| 13 | SEL (Select) | In | Printer Online Select status | Centronics 36-Pin #13 |
| 14 | AMIGA: +5V | PC: /AUTOFD | Pwr | Amiga A500/600/1200/2000/3000/4000: +5 V DC Supply (powers Plipbox!) | Amiga: +5V DC / Centronics #14 |
| 15 | /ERROR (/FAULT) | In | Printer Fault / Error status (NC on Atari ST & CPC) | Centronics 36-Pin #32 |
| 16 | /RESET (/INIT) | Out | Initialize Printer / Amiga System /RESET output | Centronics 36-Pin #31 |
| 17 | /SLCTIN / GND | Out | PC: /Select In | Amiga: Ground Return | Centronics 36-Pin #36 / GND |
| 18 | GND (CPC Even Pins 2–34) | GND | Signal Ground Return (All even bottom pins 2–34 on CPC 34-way edge) | Centronics Pins 19–30 (GND) |
| 19 | GND (0 V) | GND | Signal Ground Return | Black (GND) |
| 20 | GND (0 V) | GND | Signal Ground Return | Black (GND) |
| 21 | GND (0 V) | GND | Signal Ground Return | Black (GND) |
| 22 | GND (0 V) | GND | Signal Ground Return | Black (GND) |
| 23 | GND (-5V on A1000) | GND | Signal Ground on A500+/ST/PC (WARNING: -5V DC on Amiga 1000!) | Black (GND) |
| 24 | GND (0 V) | GND | Signal Ground Return | Black (GND) |
| 25 | GND (+12V on A1000) | GND | Signal Ground on A500+/ST/PC (WARNING: +12V DC on Amiga 1000!) | Black (GND) |
Amstrad CPC 34-Pin Edge to 36-Pin Centronics Ribbon Wiring & 7-Bit Quirk
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 & 36-Pin Centronics Cable Mapping: To save a single flip-flop chip, Amstrad used an 8-bit 74LS273 octal latch (IC108) at I/O port #EFxx where 7 bits (D0–D6, CPC Edge Odd Pins 3–15) drive Centronics 36-pin Plug Pins 2–8, and the 8th bit (D7) drives /STROBE (CPC Edge Pin 1 -> Centronics Pin 1)! Wire CPC Edge Pin 21 (BUSY -> 8255 PPI Port B Bit 6) to Centronics Pin 11, tie Centronics Pin 9 (D7) to GND so the MSB never floats high, and wire CPC Edge Even Pins 2–34 to Centronics Pins 16 & 19–30 (GND).
- 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!