E and M Signalling
Refers to PTT and the squelch indication signalling between a radio site and the control equipment.
E represents 'Ear' (what is heard, or received) and M represents 'Mouth' (what is sent). Therefore:
A PTT signal sent from the control equipment is referred to as the M signal; the same signal at the
transmitter is referred to as the E signal
A squelch indication at the receiver is referred to as the M signal; the same signal at the control
equipment is referred to as the E signal.
Squelch
Squelch (also referred to as Mute in older receivers) is a circuit function that:
Mutes a receiver's audio output during periods of no reception
Mutes a receiver's audio output when signals weaker than the squelch threshold are received.
Phantom Keying
Phantom keying is when the keying potential is superimposed on the audio lines.
Park Air T6MC Controller
Glossary of Terms
The following terms are used in this documentation.
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