[comp.dcom.telecom] Call Quality

deej@bellcore.bellcore.com (David Lewis) (06/23/89)

To get in my two cents on the discussion of call quality...

There is more to call quality than just the amount of noise on the line.
Call quality also includes Grade of Service (the percentage of a call
getting blocked somewhere in the network); call setup time; and
percentage of calls "lost".  (May be more -- that's all I can think of
right now.)

In other words, even if the calls that get through have a fabulous
signal to noise ratio, if only one in two calls get through because the
IXC doesn't have sufficient capacity to handle all the traffic, the
call quality isn't that good.  If it takes 35 seconds from end of
dialing to beginning of ringing, ditto.  If every third call gets
dropped out in the network, ditto.  (These examples are exaggerated, but
you get the picture).

Anecdote -- I changed my primary IXC from USSprint to AT&T because the
call setup times were atrocious and about one call in ten was dropping
out (end of dialing -> silence for about 15 seconds -> dial tone).
These were, of course, a small sample and all calls were from Ithaca, NY
primarily to New Jersey and Pitsburgh -- Your Mileage May Vary.  But,
the lesson is, even though the amount of the noise on the line may be
very good, the call quality may be poor.

Just a note to keep in mind...

--
David G Lewis				...!bellcore!nvuxr!deej

			"If this is paradise, I wish I had a lawnmower."