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 (the Power Macintosh 6100, 7100 and 8100), 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 ("Canneloni", Apple part M2681LL/A or 590-0796-A) or a breakout cable ("Calamari", Apple M1243LL/A or 590-0793-A) 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 (input and output), Apple Desktop Bus (ADB), 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.
+AudioVision HDI-45 pinout Pin Function 1 Analog audio ground 2 Audio input shield 3 Audio input (L) 4 Audio input (R) 5 Audio output (L) 6 Audio output (R) 7 Reserved 8 Monitor ID sense line 1 9 Monitor ID sense line 2 10 Video ground/shield (G) 11 Video output (G), 75Ω 12 Video input power ground 13 +5V for camera 14 Reserved 15 16 17 18 Monitor ID sense line 3 19 S-video input shield 20 S-video input, luminance (Y) 21 S-video input, chroma (C) 22 Reserved 23 Not used 24 Reserved 25 26 Video ground/shield (R) 27 Video output (R), 75Ω 28 I2C data signal 29 I2C clock signal 30 Reserved 31 Monitor ID 32 Monitor ID 33 Vertical sync 34 Composite sync 35 ADB power, +5V 36 ADB ground 37 ADB data 38 Keyboard switch 39 Reserved 40 41 Monitor ID 42 Horizontal sync 43 Video sync ground 44 Video ground/shield (B) 45 Video output (B), 75Ω
See also VESA Enhanced Video Connector, a similar concept to consolidate multiple cables
References
External links "HDI-45 Pinout"