[comp.dcom.telecom] Various Mysteries/Question

myerston@cts.sri.com (12/12/89)

Data over Voice (DOV) aka Speech+Plus is as old as the hills.  All it
does is use the >metallic< twisted pair bandwidth ABOVE the 4Khz voice
band for data.  Straight analog frequency division multiplexing, not
digital, not magic.

SLC-96 is the semi-generic name for Subscriber Loop Carriers.
Originally WECO using metallic pairs carrying T-1 (24 channel) PCM
multiplexed traffic.  5 T-1s per box, 1 for backup, 4 for traffic (24
* 4 = 96).  Today SLCs can carry more channels, do concentration, use
fiber etc.

Pulse/DTMF.  It is not true that only the 5ESS can detect whether a
line in coming in Pulse of DTMF.  At least the 1AESS does the same.
Parameters set by Telco decide what to do (Ignore or print on the
Maint TTY)