26 pin D-SUB connector at the SUN computer.
The Sun parallel printer port is a Centronics-compatible interface housed in a 26-pin D-sub shell, as found on Sun workstations including the Sun-3/80 (the only Sun-3-series model to include an onboard parallel port). The connector carries the standard SPP signal set — data lines D0–D7, handshake lines STROBE, ACK, BUSY, PE, and SEL, plus printer-control lines AUTOFEED, ERROR, RESET, and SELIN — on pins 1–17, with the remaining nine positions (pins 18–26) assigned to signal ground. Later Sun workstations, such as the Ultra 5 and Ultra 10, exposed an equivalent 26-pin IDC header (J8) internally, with an external bracket providing a DB-25 back-panel socket.
| Pin | Name | Dir | Description |
|---|---|---|---|
| 1 | /STROBE | OUT | Strobe |
| 2 | D0 | OUT | Data Bit 0 |
| 3 | D1 | OUT | Data Bit 1 |
| 4 | D2 | OUT | Data Bit 2 |
| 5 | D3 | OUT | Data Bit 3 |
| 6 | D4 | OUT | Data Bit 4 |
| 7 | D5 | OUT | Data Bit 5 |
| 8 | D6 | OUT | Data Bit 6 |
| 9 | D7 | OUT | Data Bit 7 |
| 10 | /ACK | IN | Acknowledge |
| 11 | BUSY | IN | Busy |
| 12 | PE | IN | Paper End |
| 13 | SEL | IN | Select |
| 14 | /AUTOFD | OUT | Autofeed |
| 15 | /ERROR | IN | Error |
| 16 | /RESET | OUT | Reset |
| 17 | /SELIN | OUT | Select In |
| 18 | GND | - | Signal Ground |
| 19 | GND | - | Signal Ground |
| 20 | GND | - | Signal Ground |
| 21 | GND | - | Signal Ground |
| 22 | GND | - | Signal Ground |
| 23 | GND | - | Signal Ground |
| 24 | GND | - | Signal Ground |
| 25 | GND | - | Signal Ground |
| 26 | GND | - | Signal Ground |
Signals
- /STROBE — active-low strobe pulse; host asserts to clock data into the printer
- D0–D7 — 8-bit parallel data bus, output from host to printer
- /ACK — active-low acknowledge from printer; indicates data received and printer ready
- BUSY — high when printer is unable to accept data
- PE — paper end; high when printer is out of paper
- SEL — select; high when printer is on-line
- /AUTOFD — active-low autofeed; host asserts to cause printer to auto-advance paper one line after each carriage return
- /ERROR — active-low error signal from printer; asserted on fault conditions
- /RESET — active-low initialise; host asserts to reset printer to power-on defaults
- /SELIN — active-low select-in; host asserts to place printer in selected state
- GND (pins 18–26) — signal ground returns for the data and control lines
Notes
The 26-pin D-sub shell accommodates one additional ground contact compared with the industry-standard DB-25 parallel port; the extra position (pin 26) carries a signal ground rather than a new signal. The signal set and logic levels are otherwise fully compatible with the Centronics SPP standard. Direction notation is from the host (computer) perspective: OUT denotes host-to-printer, IN denotes printer-to-host.