15 PIN UNKNOWN CONNECTOR
|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||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.|
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.
Contributor: Joakim Ögren
Apple Tech Info Library 1419: Apple IIc, External Pinouts at Apple TIL homepage
Copyright © The Hardware Book Team 1996-2001.
May be copied and redistributed, partially or in whole, as appropriate.
Document last modified: 2000-07-08