14 pin Apple video connector.
The original Apple iMac G3 (introduced August 1998) provides a 14-pin proprietary analogue video output connector for connecting an external display. It carries separate red, green, and blue analogue video signals with individual return lines, composite-sync-compatible vertical and horizontal sync, DDC (Display Data Channel) clock and data lines for VESA-compliant monitor identification, a +5 V supply, and a cable-detect line. The connector is compliant with the VESA DDC specification, allowing the iMac to query a connected display for its supported timings. Apple later moved to a standard VGA (DE-15) connector on subsequent iMac revisions.
| Pin | Signal | Description |
|---|---|---|
| 1 | Ground | |
| 2 | VSync | |
| 3 | Hsync | |
| 4 | Red return | |
| 5 | Red video | |
| 6 | Green | |
| 7 | Green video | |
| 8 | +5 volts | |
| 9 | Blue video | |
| 10 | DDC data | |
| 11 | DDC clock | |
| 12 | Ground | |
| 13 | /Cable detect | connected to ground in the display cable |
| 14 | Blue return |
Notes
- The video display connector is compliant with the VESA DDC specification, allowing plug-and-play monitor identification via the DDC clock (pin 11) and DDC data (pin 10) lines.
- Pin 13 (/Cable detect) is connected to ground within the display cable; the iMac detects the presence of a connected monitor by reading this line.
- The original iMac G3 Rev. A and Rev. B (August–October 1998) used this 14-pin connector. Apple’s subsequent iMac revisions adopted a standard VGA (DE-15) output.
- The iMac G3 also featured an internal undocumented expansion connector (the ‘mezzanine’ or PERCH slot) that Apple explicitly did not support; it was removed with Rev. C (January 1999). That slot is unrelated to this external video output.
- Do not confuse this connector with the Apple DA-15 Macintosh external video connector (used on the Macintosh II through beige Power Mac G3), which carries monitor-sense lines and composite sync but lacks DDC signals.
Signals
- Ground (pins 1, 12) — chassis/signal ground reference
- VSync — vertical synchronisation signal
- Hsync — horizontal synchronisation signal
- Red return — analogue return (ground) for the red video channel
- Red video — analogue red video signal
- Green — analogue green video ground/return
- Green video — analogue green video signal
- +5 volts — +5 V supply, used to power DDC and monitor identification circuitry
- Blue video — analogue blue video signal
- DDC data — bidirectional I²C data line (SDA) for VESA Display Data Channel communication
- DDC clock — I²C clock line (SCL) for VESA Display Data Channel communication
- /Cable detect — active-low line; grounded within the display cable to signal monitor presence to the iMac
- Blue return — analogue return (ground) for the blue video channel