HDI-45 connector


The HDI-45 was one of Apple Computer's proprietary cable-to-onboard video connectors. A 45-pin connector, the HDI stands for High-Density Interconnect.

Use

These connectors were used only in the first generation Power Macintosh computers, specifically connecting these computers to the Apple AudioVision 14 Display, the only display to use this connector. Other Apple displays and third-party displays could be used with a special adapter for the receptacle on the computer or a breakout cable for the permanently attached cable to the monitor that converts this unusual port to a standard DA-15 VGA connector.

Technical

In addition to carrying analog RGB video, the connector supports analog stereo audio signals, Apple Desktop Bus, and S-video input. Because the AudioVision 14 Display has front-mounted connectors for ADB and audio and video, a single consolidated cable and proprietary connector was used to simplify the connection to the computer and reduce cable clutter.
PinFunction
1Analog audio ground
2Audio input shield
3Audio input
4Audio input
5Audio output
6Audio output
7Reserved
8Monitor ID sense line 1
9Monitor ID sense line 2
10Video ground/shield
11Video output, 75Ω
12Video input power ground
13+5V for camera
14Reserved
15Reserved
16Reserved
17Reserved
18Monitor ID sense line 3
19S-video input shield
20S-video input, luminance
21S-video input, chroma
22Reserved
23Not used
24Reserved
25Reserved
26Video ground/shield
27Video output, 75Ω
28I2C data signal
29I2C clock signal
30Reserved
31Monitor ID
32Monitor ID
33Vertical sync
34Composite sync
35ADB power, +5V
36ADB ground
37ADB data
38Keyboard switch
39Reserved
40Reserved
41Monitor ID
42Horizontal sync
43Video sync ground
44Video ground/shield
45Video output, 75Ω