7 pin mini-DIN female (key in the center) connector at the DEC VAXstations, DECstations and DEC’s input adapter cables.
The 7-pin micro-DIN connector was introduced by Digital Equipment Corporation in the mid-1980s for the VSXXX family of input devices used with VAXstation and DECstation workstations. All three variants — the VSXXX-AA round 3-button ball mouse, the VSXXX-GA rectangular 3-button ball mouse, and the VSXXX-AB digitizer tablet — share the same connector and RS-232 serial protocol at 4800 bps (8 data bits, odd parity, 1 stop bit). The host system exposes a 15-pin D-sub port that splits via adapter cable (part 17-02640-01) to an RJ-11 keyboard socket and this 7-pin mini-DIN mouse/tablet socket.
| Pin | Name | Direction | Description |
|---|---|---|---|
| 1 | GND | - | Common Ground |
| 2 | RxD | IN | Receive Data |
| 3 | TxD | OUT | Transmit Data |
| 4 | -12V | - | -12V power supply |
| 5 | +5B | - | +5V power supply |
| 6 | +12V | - | +12V power supply |
| 7 | device available | The device shorts this pin to GND to let the host computer notice a plugged-in device |
Notes
Pin directions are named from the host perspective (looking at the female socket on the cable). Pin 4 (−12V) is used only by the VSXXX-AA and VSXXX-GA mice; pin 6 (+12V) is used exclusively by the VSXXX-AB digitizer tablet. The connector has a keying post in the centre that prevents mis-insertion.
Signals
- GND — signal and power return; pin 7 is also shorted to this pin inside the device to signal device presence to the host
- RxD — serial data received by the device from the host (host-to-device); 4800 bps, RS-232 levels
- TxD — serial data transmitted from the device to the host; mouse sends 3-byte incremental position packets (sync + buttons + sign bits, 7-bit delta-X, 7-bit delta-Y) at up to 55 reports/s; tablet sends 5-byte absolute position packets covering a 0–1023 count range
- −12V — negative supply for RS-232 signal levels; used by mice (VSXXX-AA and VSXXX-GA); typically −8 V to −13 V at under 20 mA
- +5V — positive logic supply for mice; +5 V ±5% at up to 150 mA
- +12V — positive supply used exclusively by the VSXXX-AB digitizer tablet; +12 V DC ±10% at 0.3 A; not present or required for mouse variants
- device available — pulled to GND (pin 1) inside the connected device; the host reads this as a logic signal confirming that a device is plugged in
References
- DECstation 5000 Keyboard/Mouse Info — cable part 17-02640-01 (GSI Darmstadt)
- DECstation 5000 Model 100 Hardware Operator’s Guide EK-PM32C-OG-003, Table C-2 (ManualsLib)
- DECstation 5000 Model 200 Hardware Operator’s Guide EK-366AA-OG-002, Table C-2 (ManualsLib)
- Linux kernel driver vsxxxaa.c — DEC VSXXX-AA/GA mouse and VSXXX-AB tablet (torvalds/linux)
- VCB02 Technical Manual AZ-GLGAB-MN, February 1986 — DEC Q-Bus Video Subsystem (Internet Archive / Bitsavers)