13 PIN 13W3 FEMALE (At the Computer).
13 PIN 13W3 MALE (At the Cable).
The NeXT Color workstation uses the DB13W3 (13W3) connector — a D-subminiature shell the width of a DB-25 carrying ten signal pins plus three large coaxial contacts (A1, A2, A3) for analogue RGB video — as its sole video output interface. Unlike other vendors that used the same physical shell, NeXT’s implementation is highly proprietary: the ten signal pins carry monitor power rails (+12 V and −12 V), a bidirectional serial monitor-identification link (Clock, Data-Out, Data-In), and ADB rather than the sync signals found on Sun or SGI variants. The display operates at 1152×870 pixels, 63.9 kHz horizontal, 60 Hz vertical, using Sync-on-Green (the sync signal is embedded on the green coaxial contact). A Y-cable splits the single 13W3 plug into a monitor connector and a separate DB-19 connection to the Soundbox peripheral.
| Pin | Description |
|---|---|
| 1 | +12 VDC |
| 2 | Power Switch Control |
| 3 | Monitor Clock |
| 4 | Monitor Out |
| 5 | Monitor In |
| 6 | -12 VDC |
| 7 | Monitor Type 2 |
| 8 | Ground |
| 9 | Ground |
| 10 | Ground |
Signals
- +12 VDC — positive 12 V supply rail powering the monitor; the 13W3 connector carries monitor power directly, unlike most workstation video interfaces.
- Power Switch Control — allows the monitor to signal the workstation to power on or off.
- Monitor Clock — serial clock for the bidirectional monitor-identification link between workstation and display.
- Monitor Out — serial data transmitted from the workstation to the monitor (Data-Out direction).
- Monitor In — serial data received by the workstation from the monitor (Data-In direction); the three-wire serial link (Clock, Out, In) identifies monitor capabilities.
- -12 VDC — negative 12 V supply rail for the monitor.
- Monitor Type 2 — one bit of monitor-type identification; combined with the serial link to communicate display characteristics to the workstation.
- Ground (pins 8, 9, 10) — signal ground returns.
The three coaxial contacts (A1, A2, A3) carry the analogue RGB signals and are not listed in the signal-pin table above. A1 carries Red video; the assignment of Blue and Green between A2 and A3 is uncertain in available secondary sources (kev009.com marks these with ‘?’). Sync-on-Green is employed, meaning the composite sync signal is superimposed on the green coaxial contact rather than carried on a dedicated signal pin.
Notes
- The 13W3 shell is physically identical to that used by Sun, SGI, and IBM workstations, but the pin assignments are entirely incompatible; connecting a NeXT monitor to another vendor’s 13W3 output risks damaging both the monitor and the host.
- NeXT systems require a proprietary Y-cable to split the 13W3 connector into a monitor plug and a DB-19 connector for the Soundbox; the Soundbox carries the ADB (Apple Desktop Bus) chain for keyboard and mouse.
- The monitor power rails (+12 V, −12 V) and Power Switch Control on the signal pins make the NeXT 13W3 wiring unlike any other workstation implementation of this connector.
- The serial monitor link (pins 3, 4, 5) is a NeXT-proprietary protocol, not compatible with DDC/EDID or any standard monitor-identification scheme.