15 pin D-SUB male connector at the
Apple computer, looking into cable-side connector.
| Pin | Signal | Description |
|---|---|---|
| 1 | TEXT | Video text signal from TMG; set to inverse of GR, except in double high-resolution mode. |
| 2 | 14M | 14M master timing signal from the system oscillator. |
| 3 | SYNC* | Displays horizontal and vertical synchronization signal from IOU pin 39. |
| 4 | SEGB | Displays vertical counter bit from IOU pin 4; in text mode, indicates second low-order vertical counter; in graphics mode, indicates low-resolution. |
| 5 | 1V SOUND | One-volt sound signal from pin 5 of the audio hybrid circuit (AUD). |
| 6 | LDPS* | Video shift-register load enable from pin 12 of TMG. |
| 7 | WNDW* | Active area display blanking; includes both horizontal and vertical blanking. |
| 8 | +12V | Regulated +12 volts DC; can drive 300mA. |
| 9 | PRAS* | RAM row-address strobe from TMG pin 19. |
| 10 | GR | Graphics mode enable from IOU pin 2. |
| 11 | SEROUT* | Serialized character generator output from pin 1 of the 74LS166 shift register. |
| 12 | NTSC | Composite NTSC video signal from VID hybrid chip. |
| 13 | GND | Ground reference and supply. |
| 14 | VIDD7 | From 74LS374 video latch; causes half-dot shift high. |
| 15 | CREF | Color reference signal from TMG pin 3; 3.58 MHz. |
Notes
- The signals at the DB-15 on the Apple IIc are not the same as those at the DB-15 end of the Apple III, Apple IIGS, and Macintosh II. Do not attempt to plug a cable intended for one into the other.
- Several of these signals, such as the 14 MHz, must be buffered within about 4 inches of the back panel connector–preferably inside a container directly connected to the back panel.