rr@chmsr (Richard Robison) (03/16/90)
Does anyone know if I can use a Mac II with an 8-bit color video card with
an IBM EGA or VGA monitor? Thanks.
-Richard
Richard Robison
Computer Coordinator, ISyE 404-894-6221
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INTERNET: rr@isye.gatech.eduperry@key.COM (Perry The Cynic) (03/17/90)
In article <7090@hydra.gatech.EDU> rr@chmsr.gatech.edu (Richard Robison) writes: > Does anyone know if I can use a Mac II with an 8-bit color video card with > an IBM EGA or VGA monitor? Thanks. > Richard Robison EGA: no way. EGA (only) monitors are 6-bit *digital* RGB. The Mac produces *analog* RBG signals. (And yes, in theory you can make a converter box, but it's definitely not worth the trouble.) Also, EGA resolution (640x350) is low compared to typical Mac display cards. VGA: depends. It depends on what you consider to be a VGA monitor. If you talk about the "official" IBM VGA monitor(s), they are analog RGB. However, the Mac's display cards use a "composite" synchronization signal, while the VGA (non-)standard requires separate horizontal and vertical sync signals. Again, you can make a converter box. This may actually be feasible, if you are proficient at electronical gadgeteering. (You need to split up the sync signal into its two components.) If you need to pay somebody to build the box, it's probably not cost effective (i.e., buying a monitor is cheaper). I don't know of anybody who sells such a converter box off the shelf. If you happen to look at a multi-synchronous (multisync/multiscan-type) VGA-capable monitor, you need to check whether it is able to accept a "composite synchronization" signal. The Sony 1302A for one does (it goes through lots of contortions to be compatible - if you don't give it a sync signal at all, it will latch onto the green color signal and derive its synchronization from there). On the other hand, there are lots of multi-frequency PC monitors that *don't* accept composite sync signals. Be wary. -- perry -- -------------------------------------------------------------------------- Perry The Cynic (Peter Kiehtreiber) perry@arkon.key.com ** What good signature isn't taken yet? ** {amdahl,sgi,pacbell}!key!perry