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Sym. Terminal Cables
Date: Thu, 15 Oct 87 12:28:39 PDT
From: KELLY%PLU@ames-io.ARPA
Anyone know where I can get cables to connect Symbolics terminals to the
CPUs at a less outrageous price than Symbolics charges? Please address
responses to kelly@ames-pluto.arpa.
Jim Kelly
I have the following information:
The connector is manufactured by the Japanese company HIROSE. The cable is
75 ohm coax (for the video) and 4 twisted pairs. The cables have males at
each end. Its made for Symbolics by GORE. There are twelve pins:
5
4 6
11 12
3 7
10
2 8
1 9
1: AUDIO XMIT-
2: AUDIO XMIT+
3: SERIAL BIPHASE TXD-
4: SERIAL BIPHASE TXD+
5: SERIAL BIPHASE RXD-
6: SERIAL BIPHASE RXD+
7: AUDIO CLK OR RCV-
8: AUDIO CLK OR RCV+
9: PHASE ENCODED VIDEO
10: VIDEO GROUND
11: SERIAL GROUND
12: GROUND
I would guess this means that the wiring on the cable is straight-through.
This is for the newer (post '83) 36xx. The older machines use a LEMO cable,
and apparently the connectors are no longer available.
The diagram from UPENN is correct for the cables for Hirose connections.
An earlier diagram distributed by Symbolics had the video signal and
ground gratuitously transposed, and this gave us grief in building
cables longer than a few feet. Gore will sell you the cable, but they
want $4/ft for short lengths, and $11/ft for 200' type lengths. This is
picking in the HIGH cotton! Since we were unable to locate any other
source of a cable small enough to fit in the strain relief of the
Hirose, we resorted to building boxes that use cheapo cable to connect
them together, and have female Hirose connectors on them for short
male-to-male Hirose cables to hook up the CPU and the console. For runs
of only a couple hundred feet, RG-59 coax is fine for the video, and
most any shielded cable of twisted pairs will do. For runs up to about
500 ft, we've use RG-6 coax and independently shielded 25 gauge twisted
pairs. We've had a bit of trouble with the audio on just one such
cable, so that may be stretching the flakey driver/receiver stuff used
for audio. I'll have to experiment with whether a line of coax for each
twisted pair would allow a much longer run.... In theory, switching the
video onto RG-11 should be good for more than 1000 ft... we just haven't
had the need to do this experiment.
After we built a "cable transition box", Symbolics started to sell just
that sort of thing. It uses an Ampex parallel push-pin style connector
for the 4 twisted pairs and their common shield, plus BNC connectors for
the coax, and exposes a male BNC and a female Hirose on the front panel.
It is designed for installation in a standard electrical wall box. We
bought a bunch of these despite the rather steep cost of (at that time)
$45 each, and wired a dozen or so offices to a patch panel in our
machine room. Hirose cables 20 to 50 feet long connect the CPUs to the
panel, and 10 ft Hirose cables in the offices connect the boxes to the
consoles. When we needed more boxes recently, we ordered them and heard
the following bad news: they now want $150 each for them, and they are
backordered until enough orders accumulate to justify a manufacturing
run. Well, at theat price I suspect it only takes a few orders to make
a profitable manufacturing run, but I also suspect that not too many
people will rush to order them. So we started looking for second
source; if we find one we'll report it to SLUG... if we don't find one,
we may have to waste our own technicians' time designing and building
some for in-house use. Too bad Symbolics has fallen onto such weird
times....
this stuff came over the slug list a while ago. I don't beleive that the black GORE
cable is rated for ceilings (its covering is gore-tex not teflon - its that Gore...)
we use the boxes (ouch!, but it would be even more to do it ourselves, the only
people we have here that know how to solder cost too much to have making boxes)
<dp>