[VoiceOps] Letting a phone ring forever?

Tim Jackson jackson.tim at gmail.com
Tue Jul 26 14:51:15 EDT 2011

I think the default timer for ISUP calls between ACM and ANS is somewhere
around 1.5 -> 3 minutes usually.. You won't find anywhere that allows much

ISUP T9 timer I think, but that may not be useful for ANSI ISUP..

On Tue, Jul 26, 2011 at 1:33 PM, Jay Hennigan <jay at west.net> wrote:

> On 7/26/11 11:09 AM, Carlos Alvarez wrote:
> > We have a customer who has asked us to let his main line ring "forever"
> > or at least five minutes.  As a standard practice we forcefully hang up
> > on an unanswered call at 90 seconds if the customer has turned off
> > voicemail and auto-attendants.  It seems wrong to let a line ring
> > forever or even for minutes at a time, and I recall something in the
> > back of my head about a traditional industry-standard limit.
> Interfacing to conventional telephony devices gets kind of sticky in
> these cases.  If the line hasn't been seized and returned answer
> supervision then there is no way to signal the originating device to
> tear down the call from the end switch.  The originating switch can time
> out and tear down the call without supervision of course.  And that is
> likely to be the issue with honoring your customer's request.
> The main obstacle to letting it ring forever is that even if *you* set a
> ridiculously long timeout, the rest of the world calling his main line
> isn't going to be inclined to follow suit.  Virtually all carriers on
> the originating side will treat the call as abandoned after some time
> that is likely going to be less than 300 seconds.  Cellular carriers
> especially are going to be aggressive about tearing down calls that are
> consuming airtime and not generating revenue.  Likewise long distance
> and international carriers.
> Back in the good old days of various colored boxes, it wasn't uncommon
> to have calls that weren't officially answered (OK, technically they
> were *very* briefly answered) that would last for an hour or more.  I
> don't personally know how any of this was done, of course.  ;-)
> --
> Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net
> Impulse Internet Service  -  http://www.impulse.net/
> Your local telephone and internet company - 805 884-6323 - WB6RDV
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