clemon@lemsys.UUCP (Craig Lemon) (09/28/90)
Hi everyone. My question concerns a switching method for RGB
montior inputs.
Just a little background. I have an Amiga 2000 with an IBM
Bridgecard. For those of you not knowing what I mean, this means that I
have a small IBM motherboard that plugs into my computer and allows you to
run IBM software AND use IBM cards (there are dedicated slots for these
cards) including video, networking, HD and accelerator cards ad infinitum.
The Amiga (stock) runs with a horizontal scan speed of 15.75 kHz and uses
analog RGB. An upgrade is available through several means (dedicated video
card with all modes and new modes on a chip) to boost some or all video
modes to 31.5 kHz. I am also interested in running a video card on my IBM
to improve from CGA (ich!). I would also like to build an NTSC-RGB
convertor. Here is where my problem starts.
I have an NEC Multisync II that I use solely for my Amiga stock
display right now. I would like to use switch to select between Amiga and
IBM displays. At some point I will probably have to switch between four
inputs - Amiga stock, Amiga enhanced, IBM, NTSC. I realize that switches
can be bought but even for a two-way switch it is very expensive. I am not
positive but I also believe that you are not to switch inputs while the
hardware is on. I was wondering if it was possible to build an electronic
switch that would be clean enough to switch while power is applied and
inexpensive enough that I can afford an IBM video card :-). I realize that
this would not be TOO difficult if I didn't have the analog signal to deal
with. What about some sort of FET setup to open and close channels? Is
there a chip that will allow me to switch a number of lines on and off
regardless of what flows on them? ANY input whether about sources for
pre-fab switches, truth about switching while power is on, or the
construction of an electronic switch is appreciated/needed. How do others
out there deal with multiple video problems?
On a related topic, what about parallel port switches? Try to find
a 25PDT switch ! :-) :-).
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Craig Lemon - Kitchener, Ontario. Amiga B2000/10--2400 bps--AmigaUUCP 1.03D
lemsys!clemon@xenitec.on.ca or ....!{uunet}!watmath!xenitec!lemsys!clemon