I
was helping to configure a new board room. This one is a tiny bit
different by having two nice big TVs mounted on the walls and the cable
run to each is at least 30m. So - HDMI does not reliably go that far
over copper cable (I know - somebody always has an example where they've
made it work, but this has to be reliable!). It's probably why so many
training/presentation rooms still have SVGA on the desk plate; it's
reliable.
The
other requirement was that with no operational changes you should be
able to plug an HDMI laptop into the desk plate and "...it just works"!
So - Barnfind are my favourite fibre parts and so a couple of BarnMini03 & 04s
with single-mode fibre between (spliced, of course!) takes the HDMI up
to 80km. I used these nice wall-termination panels from ADC Krone.
I also bought one of those cheap no-name HDMI splitter/DAs from Amazon as I've had no trouble with them in the past - they even work well as HDCP removers.
However in this case as soon as I plugged in the second TV the system
would fall over with the "signal present" light on the DA going out - TV
A or B could be fed individually but not together. Sticking the EDID
analyser on the feed to the DA i/p showed the DA was generating and EDID
exchange ever second or so and alternating between the two different
EDIDs - first Mr. Sony then Mr. LG (different models of screens).
So,
after a bit of head-scratching I put one of these on the input of the
DA - it essentially answers EDID enquiries without forwarding them
upwards. Works like a charm;
My
next test will be to see if the DA pulling the hotplug detect pin low
and triggering the erroneous EDID exchanges. For this I need to dig out
one of my famous Root6 Spoof'o'matics which we had manufactured in
quantity after a similar problem with Avid and how it reacts to different monitors.
