| 15 Pin Connector | Signal | Description |
| 1 | TEXT | Video text signal from GLU |
| 2 | 14M | 14MHz Timing signal from master oscillator |
| 3 | SYNC | Display synchronisation signal from IOU pin 39 |
| 4 | SEGB | Display Vertical counter bit from IOU pin 4 |
| 5 | 1VSOUND | 1v sound signal |
| 6 | LDPS | Video shift Register load enable |
| 7 | WNDW | Active area display blanking |
| 8 | +12v | Regulated +12v |
| 9 | PRAS | Ram row address strobe |
| 10 | GR | Graphics mode enable |
| 11 | SEROUT | Serialized character generator output |
| 12 | NTSC | Composite NTSC video signal |
| 13 | GND | Ground |
| 14 | VIDD7 | Causes half dot shift if high |
| 15 | CREF | Colour reference signal |