Q: What type of video port is this?
From Hardware
The Rainbow's video port is DEC's proprietary standard. It is meant for connection to a VR201 or VR241 monitor. The monochrome video signal is standard TTL composite. The color signals are sync-on-green. The video port pinouts are as follows:
| Pin | Signal |
| 1 | Red Shield Ground |
| 2 | Green Shield Ground |
| 3 | Blue Shield Ground |
| 4 | Mono Shield Ground |
| 5 | Ground |
| 6 | Ground |
| 7 | +12 volts |
| 8 | +12 volts |
| 9 | Blue Video |
| 10 | Green Video |
| 11 | Red Video |
| 12 | Mono Video |
| 13 | not used |
| 14 | Data from Keyboard to CPU |
| 15 | Data from CPU to Keyboard |
The color signals are only present if the Rainbow Color/Graphics Option is installed.