Macintosh IIci, IIsi, LC, and LC II: Video Pinouts


Article Change History
----------------------
02/03/93 - CORRECTED
* The IIci and IIsi do support the Apple Portrait Display with
built-in video.
02/03/93 - UPDATED
* Added information from article titled "Macintosh IIsi, IIci,
LC: Monitor Compatibility"
09/15/92 - REVISED
* To clarify what monitors the IIci & IIsi video port supports.


What are the differences between the Macintosh IIci on-board video pinouts
and signals versus the Macintosh IIsi, Macintosh LC, and Macintosh LC II?
What pin can I "sense" to see a 13-inch RGB monitor connected when there is
none connected (that is, testing a projector connected but with no monitor
attached)?


Pinouts
-------

The Macintosh IIci, Macintosh IIsi, Macintosh LC, and Macintosh LC II have
the same pinouts for their built-in video ports:

Pin Function
--- -----------------
1 Red Video GND
2 Red Video
3 CSynch
4 Mon. ID 1
5 Green Video
6 Green Video GND
7 Mon. ID 2
8 N.C.
9 Blue Video
10 Mon. ID 3
11 CSynch and VSynch GND
12 VSynch
13 Blue Video GND
14 HSynch GND
15 HSynch
Shell Shield GND


Sense Codes
-----------

Hor x Vert Band- Vert Horiz
Sense Pins Pixels width Refresh Scan
10 7 4 Display (MHz) (Hz) (KHz)
--------- ------- ---------- ------- ------- -----
0 0 1 Apple Portrait Display 640 x 870 57.2832 75 68.9
0 1 1 Apple Two-Page Mono Monitor 1152 x 870 100 75 68.7
0 0 0 Macintosh 21" Color Display 1152 x 870 100 75 68.7
1 1 0 12" Apple Monochrome Monitor 640 x 480 30.24 66.7 35.0
1 1 0 13" AppleColor RGB Monitor 640 x 480 30.24 66.7 35.0
0 1 0 12" AppleColor RGB Monitor 512 x 384 15.6672 60.15 24.48
1 0 0 Interlaced display - 12.2727 - 15.7

0 - Grounded 1 - Not Connected


Extended Sense Codes
--------------------

Hor x Vert Band- Vert Horiz
Sense Pins Pixels width Refresh Scan
4-10 7 Display (MHz) (Hz) (KHz)
--------- ------- ---------- ----- ------- -----
0 1 Macintosh 16" Color Display 832 x 624 57.63 75 49.7

0 - Tied Together 1 - Not Connected


Configurations
--------------

Macintosh Macintosh Macintosh
LC/LC II IIsi IIci

12" RGB Display X X X
12" Monochrome X X X
High-Resolution RGB X X X
Portrait Display - X X
Two-Page Display - * *
16" Color Display - * *
21" Color Display - * *

(X indicates compatibility, * indicates the need for a NuBus interface)

In the case of the Macintosh IIsi, you need to install a NuBus Adapter Card
first.


VGA Compatibility
-----------------

To connect a VGA monitor to the Macintosh LC or LC II video port, a cable
with the following configuration is required. Third-party cable vendors
should have these cables available for purchase.


Macintosh LC/LC II
DB-15 VGA Connector
------------- --------------

2 ------------------- Red Video ------------ 1
1 ------------------- Red Ground ----------- 6
9 ------------------- Blue Video ----------- 3
13 ------------------- Blue Ground ---------- 8
5 ------------------- Green Video ---------- 2
6 ------------------- Green Ground --------- 7
15 ------------------- Hsync ---------------- 13
12 ------------------- Vsync ---------------- 14
14 ------------------- Sync Ground ---------- 10
10 ------------------|
7 ------------------|Connect 7 and 10 so the sense pin ID will equal VGA

A few issues to remember when connecting VGA monitors to the
Macintosh LC or LC II:

* VGA monitors may have variances when purchased from different VGA monitor
vendors. It is suggested that a particular monitor be tested for
compatibility with the Macintosh LC or LC II before making a purchase
decision.

* VGA monitors from different vendors have different image quality
specifications. There may be significant differences between the Apple
logo monitors and the VGA monitors. A side-by-side review of the
monitors should be done before deciding which monitor to buy.

* When a VGA monitor is connected as described above, the resolution is
640 x 480. The bit-depth supported depends on the amount of VRAM
installed. If the Macintosh LC 256K VRAM SIMM is installed, 4-bit color
(16 colors) is supported. With the Macintosh LC 512K VRAM SIMM
installed, 8-bit color (256 colors) is supported.

Published Date: Feb 18, 2012