On Tue 25 Jun at 18:31 David Drummond (3:640/305{at}fidonet) wrote to Arthur Marsh:

 DD> What is meant by PCM channels?


One PCM channel:

         |---|  |---|
modem ---|A/D|--|D/A|--- modem 
         |---|  |---|

Two PCM channels:

         |---|  |---|   |---|   |---|
modem ---|A/D|--|D/A|---|A/D|---|D/A|--- modem
         |---|  |---|   |---|   |---|

PCM stands for Pulse Code Modulation. With one PCM channel, there is one
analogue to digital and one digital to analogue conversion. With two PCM
channels there are two analogue to digital and two digital to analogue
conversions.

--- msgedsq 2.1