forrette@sim.berkeley.edu (Steve Forrette) (07/16/90)
Occasionally someone mentions in the Digest about how the telcos refuse to return answer supervision to the originating party. I've discovered something that some of you no doubt are already aware of, but many of you may not know: If you have three-way calling, you can determine when the call supervises. This is a result of a flash not breaking to a second dial tone until the call supervises. For example, let's say I call a certain number. At any time before the person answers, if I flash the line, nothing happens. As soon as the person answers, a flash will obtain the secondary dialtone. At least this is what happens on the 1AESS I'm on. If the call never supervises (no answer, "out of service" recording, etc.), a flash will never obtain secondary dialtone. This seems to work whether the call is local or long distance, although the propagation delay of the supervision back to my originating office is of course longer when calling inter-state. A couple of notes: If you flash after the last digit is dialed, but before the 1st audible "click", the call terminates, and you get a "fresh" dialtone. And, if you call a number on the same switch, there is no period where a flash will be ignored. The call in progress will be terminated if you flash before supervision, or you will get secondary dialtone if you flash after supervision. A couple of questions for you experts: Does this only happen on a 1AESS? Which other switches? Also, what are the "official" minimum and maximum on-hook durations for a flash? Of course, everyone I've tried to ask at Pacific Bell doesn't even understand the question. It's the typical routine - "Sir, I don't understand what you're asking me, and I won't connect you with someone that does. Now how can I help you?"
bote@uunet.uu.net (John Boteler) (07/20/90)
From article <9782@accuvax.nwu.edu>, by forrette@sim.berkeley.edu (Steve Forrette): > If you have three-way calling, you can determine when the call > supervises. This is a result of a flash not breaking to a second dial > tone until the call supervises...At least this is what happens on the > 1AESS I'm on. > A couple of questions for you experts: Does this only happen on a 1AESS? > Which other switches? As you succinctly pointed out, this is what happens on your 1A, but not on mine. Don't ask about #5s around here. I rather fancy this, as a matter of fact; each switch has its own personality :) Too bad for us when we build circuits and install equipment depending on predictable behavior. Postscript: On 1A Centrex around here (D.C.), answer supervision was provided in the form of loop-interrupt. If you really, really needed to have this information provided you, just order Centrex (and hope they get the features right!) John Boteler {uunet | ka3ovk}!media!csense!bote NCN NudesLine: 703-241-BARE -- VOICE only, Touch-Tone (TM) accessible