Apple Computer Video Buses

This listing only relates to Apple Video interfaces. The main page for Apple buses is listed on the Apple Computer Buses page.

Different types of Apple computer Video buses are listed on this page. The Macintosh computer is a sub-type of Apple computer. The computer monitor bus pinout for different types of interfaces is listed below. A description is provided along with the connector pin outs. How ever, no electrical standards or cabling information is provided.
Here is a link to Connector manufacturers, or Cable manufacturers, and a list of Cable Assemblies manufacturers.

Designer Note: Watch for the reference to obsolescence in some of the bus listings below.

34-Pin Apple Display Connector [ADC] Bus D-Sub Pin out

The Apple display connector [ADC] is an Apple proprietary interface connector. The ADC pinout and function is similar to the DVI connector and carries both digital and analog video signals, but the pin out is different and the ADC uses the USB bus. The ADC Video bus has control signals and power for an external monitor. Note: the physical size and shape of the ADC connector is different from the DVI connector and they will not mate together. A maximum current of 3.6 amps may be drawn via the 25 volt power pin. Apple computers may also be found with DVI connectors.
The video card and type of computer determines which interface is provided.

34 pin ADC Connector Pinout and Signal names
Pin # Signal name Pin # Signal name Pin # Signal name
1 25v Supply 11 25v return 21 USB Data+
2 25v Supply 12 25v return 22 USB Data-
3 LED 13 Soft Power 23 USB Return
4 TMDS Data0- 14 TMDS Data1- 24 TMDS Data2-
5 TMDS Data0+ 15 TMDS Data1+ 25 TMDS Data2+
6 TMDS Data 0/5 Shield 16 TMDS Data 1/3 Shield 26 TMDS Data 2/4 Shield
7 TMDS Data5- 17 TMDS Data3- 27 TMDS Data4-
8 TMDS Data5+ 18 TMDS Data3+ 28 TMDS Data4+
9 DDC Data 19 DDC Clock 29 Clock+
10 Vsync 20 Clock Return 30 Clock-
C1 Analog Blue Video -- -- -- --
C2 Analog Green Video -- -- -- --
C3 Analog Horizontal Sync -- -- -- --
C4 Analog red Video -- -- -- --
C5 Analog GND Return: (analog R, G, B) -- -- -- --

Apple S-Video Pin out

The Video Bus page provides a description of the S-Video bus.
However the S-Video standard uses a different style connector.

Apple S-Video Connector pin configuration

7 Pin Special Mini-DIN
Pin Number Description
1 Analog GND
2 Analog GND
3 Video Y (Luminance)
4 Video C (Chroma)
5 I2C Clock
6 +12 VDC (max 250mA)
7 I2C Data

Apple II Video Expansion Pin out

This bus interface is obsolete.

Video Pin-Out
Pin name 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 pin39
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 1VSOUND 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

Apple Video Mirror Pin out

This bus interface is obsolete

22 Pin Connector
Pin name Description
1 VID.GND Video ground
2 RED Red signal
3 GREEN Green signal
4 VID.GND Video ground
5 VID.GND Video ground
6 BLUE Blue signal
7 CSYNC C sync
8 VSYNC Vertical sync
9 MLB.SYNC.EN.L Not used (reserved)
10 HSYNC Horizontal sync
11 DAC.ISET.1 Not used(reserved)
12 DAC.ISET.2 Not used (reserved)
13 SND.GND Not used (reserved)
14 SND.RIGHT Not used (reserved)
15 SND.LEFT Not used (reserved)
16 +5V +5 volts
17 GND Ground
18 SDAT Not used (reserved)
19 SCLK Not used (reserved)
20 +12V +12 volts
21 -12V -12 volts
22 Dot Clock Scaled dot clock (scaled to 10 percent)

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Modified 7/18/2015
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