In article ,
Howard James wrote:

I'm building an EchoLink interface and one of the signals to the tranceiver
is COR.

What does COR stand for please?

I have no reference to COR in my Kenwood TS2000 manual. I suspect it may
have something to do with squelch.

COR is (I believe) an acronym for "Carrier Operated Relay", and is
often referred to these days as "COS" ("Carrier Operated Squelch").

It's a signal which comes from a receiver of some sort, which means
"I'm detecting a sufficiently strong carrier to 'believe' that there
is an incoming signal of some sort."

Just what this signal actually indicates, depends on the radio. It
might be from RF detection in the front end, or be based on the
S-meter circuitry in an FM limiter/discriminator, or might be based on
a reduction in the noise level in the signal coming out of the FM
discriminator (the latter is most common in VHF FM radios).

In the case of a COR signal coming out of an Echolink or similar
interface, it would be controlled by software, and I'd imagine that it
probably means "We're receiving incoming audio packets via the
Ethernet." You'd feed it (possibly with inversion and/or buffering)
to the PTT input to your transceiver.

If it's intended as an *input* to the Echolink interface, then it
would probably be connected to a "signal arriving, speaker on!" output
from your transceiver... but most transceivers don't have one of these.

--
Dave Platt AE6EO
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