[comp.dcom.telecom] Why Does It Take So Long To Have a Number Dial?

tjrob@ihlpl.att.com (Thomas J Roberts) (02/21/90)

 From article <4107@accuvax.nwu.edu>, by doug@letni.uucp (Doug Davis):
 
> Here's a question for those in the know. I just moved into a new area
> 214-270-XXXX is the area code and prefix.  What I would like to know
> is why it takes so long for my exchange to "make" a connect.

In many (most?) end offices, typing a # after the number will avoid
any post-dial delay. Some systems cannot determine when dialing is
completed by looking at the dialed digits, so they simply wait for
several (8-10) seconds of silence, and assume that signals the end of
dialing. Most will accept a # to also signal end of dialing. If you
are using dial-pulse (instead of DTMF), I believe you are out of luck.
Most modern end offices determine end-of-dialing by examining the
dialed digits, UNLESS THERE IS AN AMBIGUITY INHERENT IN THE DIALING
PLAN. Note that you may not be aware of the ambiguity.

There are many other causes of post-dial delay. The above paragraph
describes the only portion that you, the subscriber, can do anything
about (short of moving to another end office, or changing your
long-distance company).


Tom Roberts
AT&T Bell Laboratories
att!ihlpl!tjrob