13 PIN 13W3 FEMALE (At the Computer).
13 PIN 13W3 MALE (At the Cable).
The Sun SPARC workstation family used the 13W3 (DB13W3) connector as its standard video interface from the early 1990s SPARCstation line through the mid-2000s Ultra workstations. The shell is physically identical to a DB-25 but carries ten signal pins alongside three large coaxial contacts (A1/A2/A3) for Red, Green, and Blue analogue video — the designation “13W3” reflects 13 contacts with 3 coaxial. No single ANSI or EIA standard governed 13W3 pin assignments, so Sun’s implementation differs from SGI, IBM, and NeXT despite sharing the same physical shell. Sun systems carry composite sync only (pin 5), three monitor-sense bits (pins 3/8/9) that the host reads at boot to select the appropriate resolution and refresh rate, and no separate horizontal or vertical sync in normal operation.
| Pin | Name | Description |
|---|---|---|
| 1 | GND | Ground* |
| 2 | VSYNC | Vertical Sync* |
| 3 | SENSE2 | Sense #2 |
| 4 | SENSEGND | Sense Ground |
| 5 | CSYNC | Composite Sync |
| 6 | HSYNC | Horizontal Sync* |
| 7 | GND | Ground* |
| 8 | SENSE1 | Sense #1 |
| 9 | SENSE0 | Sense #0 |
| 10 | CGND | Composite Ground |
| R | RED | Red |
| G | GREEN/GRAY | Green/Gray |
| B | BLUE | Blue |
- ) Considered obsolete, may not be connected.
Monitor-sense bits defined as:
| Value | Bit 2 | Bit 1 | Bit 0 | Resolution |
|---|---|---|---|---|
| 0 | 0 | 0 | 0 | ? |
| 1 | 0 | 0 | 1 | Reserved |
| 2 | 0 | 1 | 0 | 1280 x 1024 76Hz |
| 3 | 0 | 1 | 1 | 1152 x 900 66Hz |
| 4 | 1 | 0 | 0 | 1152 x 900 76Hz 19" |
| 5 | 1 | 0 | 1 | Reserved |
| 6 | 1 | 1 | 0 | 1152 x 900 76Hz 16-17" |
| 7 | 1 | 1 | 1 | No monitor connected |
Signals
- RED (A1) — Analogue red video signal carried on coaxial contact A1.
- GREEN/GRAY (A2) — Analogue green (or greyscale) video signal on coaxial contact A2; Sun does not use sync-on-green, unlike SGI.
- BLUE (A3) — Analogue blue video signal on coaxial contact A3.
- GND (pins 1, 7) — Signal ground; marked obsolete on later Sun hardware and may be unconnected.
- VSYNC (pin 2) — Vertical sync; present on early Sun 13W3 implementations but marked obsolete and typically not connected in later systems.
- SENSE2 (pin 3) — Monitor-sense bit 2 (most-significant bit of the 3-bit sense code).
- SENSEGND (pin 4) — Sense return ground; common return for all three sense lines.
- CSYNC (pin 5) — Composite sync (horizontal and vertical combined); the primary sync signal on all Sun 13W3 implementations.
- HSYNC (pin 6) — Horizontal sync; present on early Sun 13W3 implementations but marked obsolete and typically not connected in later systems.
- SENSE1 (pin 8) — Monitor-sense bit 1.
- SENSE0 (pin 9) — Monitor-sense bit 0 (least-significant bit of the 3-bit sense code).
- CGND (pin 10) — Composite sync return ground.
Notes
- The 13W3 shell is mechanically identical to a DB-25; a DB-25 cable will fit but carries no valid signal.
- Sun’s three monitor-sense pins (SENSE0/1/2) form a 3-bit code that the workstation reads at power-on to identify the attached monitor type and automatically configure the frame buffer’s output resolution and refresh rate without user intervention.
- Pins 1, 2, 6, and 7 are present in the connector but are considered obsolete on the SPARCclassic and later Sun hardware; they originate from the very earliest Sun workstation video implementations and are left unconnected on most monitors and cables.
- Sun 13W3 uses composite sync on pin 5 and does not rely on sync-on-green; this distinguishes Sun cabling from SGI 13W3 cabling, which routes sync through the green coaxial contact.
- Cross-vendor 13W3 adapters between Sun, SGI, IBM, and NeXT systems require rewiring because each manufacturer assigned its own sync and identification signals to the ten standard pins.