[GreenKeys] ASR-28 Perf. Question

[Jack]

Tom,

You'd have to put the reperf on it's own loop and then switch
the loop connection in and out of your ST-6's loop. In two of my
28ASR's I have an extra loop supply and polar relay operating the
reperf. The "line" side of the polar relay goes in series with the
station loop (to the terminal unit). The relay then keys the
reperf.
If I want the reperf out of the station loop, I simply put a short
(with a switch) across the polar relay contacts that key the
reperf. That way the
reperf stays in the MARK condition, ignoring the incoming signals
on the polar relay. Another "modern" way to do this is to use a
Teletype
"Selector Magnet Driver" which is a solid state version of the
polar relay/loop configuration. These gadgets are hard to find.
Most 28ASR's have the 300 MA. loop supply on the LESU and you can
grab
the needed loop voltage from it...then all you would need is the
polar relay and the switch. The "TEST" switch on many ASR's
puts everything in series and/or reconfigures the hookup based
up a pre-determined test scenario. I'd steer away from using that
switch...it would take a lot of connection tracing and rewiring.
Since the keyboard reperf has a selector, it's real easy to get to
the
connections.
If you need a simple schematic, let me know.

73,
Jack WA2HWJ

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