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Apple Video Cards & Monitors

DataPro Tech Info > Apple Video Cards & Monitors

Apple NTSC is not compatible with any other RGB, TTL or Analog types. It is used with Apple IIc and some others. It uses the DB15 2-row connector, just like the MAC series, but is electronically different.

Apple Native refers to on-board (not removable) video ports.

Apple frequency is 75 hz, VGA is 60 hz (vertical refresh rate).

The original MAC II (without any modifying letters) is an 8-bit video card and is NOT compatible with any VGA, RGB or others. It can only be connected to an Apple or clone monitor. It has composite sync only, not separate Horz and Vert sync.

The newer MAC IIs such as MAC IIsi, MAC IIci, etc. are all 16-bit, the same as the LC, Quadra, Centris, etc. The Quadra AV is switch selectable to use either 75 hz or 60 hz frequency.

As of 12-31-93, to my knowledge and according to John Amoratta at MicroMatch, all Apple monitors support COMP SYNC only, not separate Horz and Vert Sync, and therefore cannot be used with VGA or RGB cards. Also, Apple monitors run at 75 Hz frequency, VGA is 60 Hz.

Due to frequency difference, the strapping in the pinout must sometimes be artificially set to the next lower resolution type in order to work.

In other words, an 1152 x 870 VGA monitor at 60 hz will only be capable of 1024 x 768 at Apple's 75 hz. This is not true in all cases, but is generally true when the resolution is pushed to the maximum capability of the monitor. Thus, a monitor capable of 1152 x 870 that is receiving a 640 x 480 signal will not care which frequency is used.

The monitor's maximum limit is a PRODUCT of both the resolution rating and the signal frequency. To achieve maximum resolution, a lower frequency must be used. The lower the frequency, the higher the potential resolution.

The pinouts for Apple MAC computers to VGA type monitors are in the following files:

    117006.CFG      DB09M for Sony MultiScan 
    117565.CFG      MAC II Native to NEC MultiSync 3D, Sony CPD-1304S 
    117575.CFG      MAC LC,Quadra to NEC MultiSync 3D 640 x 480 (COMP) 
    117595.CFG      MAC LC,Quadra to Hi-Res 1024 x 768 
    117535A.CFG     Apple 16 bit to VGA  640 x 480 @ 66 Hz 
    117535B.CFG     Apple 16 bit to VGA  832 x 624         
    117535C.CFG     Apple 16 bit to VGA  640 x 480 @ 60 Hz 
    117535D.CFG     Apple 16 bit to VGA 1024 x 768            
    117535E.CFG     Apple 16 bit to VGA 1152 x 870         
    117535F.CFG     Apple 16 bit to VGA  w/ Comp Sync      

The following chart shows the strapping of sense pins (Monitor ID pins) used for various non-standard monitor types.

Name or Description         Resolution  Freq    Sense Pin strapping 
------------------------    ----------  ----    ------------------- 
Apple 21 Inch Color         1152 x 870  75hz    None 
Apple Portrait Display       640 x 870  75hz    04,11 
Apple 12 Inch RGB            512 x 384  60hz    07,11 
Apple 2-Page Display        1152 x 870  75hz    04,07,11 
Apple 16 Inch Color          832 x 624  75hz    04,10    
PAL Option 1 UnderScan       640 x 480  50hz    04,07,10   (Diode @ 7-10) 
PAL Option 1 Over-Scan       768 x 576  50hz    04,07,10   (Diode @ 7-10) 
PAL Option 2 UnderScan       640 x 480  50hz    04,07      (Diode @ 7-10)  
PAL Option 2 Over-Scan       768 x 576  50hz    04,07      (Diode @ 7-10) 
VGA                          640 x 480  60hz    07,10 
SVGA                         800 x 600  56hz    07,10      (Select SVGA) 
Apple 19 Inch Color         1024 x 768  75hz    04,07