[VoiceOps] Letting a phone ring forever?

Jay Hennigan jay at west.net
Tue Jul 26 14:33:34 EDT 2011

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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