[Asterisk-Users] Distinctive ringing

[Rich Adamson]

> Does  asterisk know when each ring comes in or just the first ring, ie 
> so the cadence can be worked out? say over two rings?
> 
> Robb
> Martin Pycko wrote:
> 
> >The X100P together with asterisk does not support the distinctive ringing
> >detection on the line. Asterisk however can generate the distinctive ring
> >over FXS ports.
> >
> >regards
> >Martin
> >

I just installed two new x100p cards in the last two weeks; one used on
a residential line, the second on a business line (CO Centrex). The business
line rings with a Long and a Short within the same time period as a normal
ring, which is essentially distinctive ringing. In many US pbx's (and 
obviously this CO Centrex) the ring is intended to represent a call 
arriving from an outside line (as opposed to another CO Centrex line). 
Asterisk failed to recognize the callerid as it believed the callerid 
data arrived after the "second" ring (when it fact, it was arriving exactly 
where it was suppose to by pure telephone standards).

I opened a problem with Digium late last week. One of their techs logged
into this system, tested with real calls, and observed the problem. They made
a source code change in chan_zap.c (and possibly others) and now callerid
works fine with that distinctive ring. Since I don't have another copy of
the cvs that was in use at the time, I don't know what they changed. I've
asked multiple times, but never get a response from the support folks.
Therefore, I'm not sure if they fixed a real bug or if they brute-forced
"this" system to look for callerid elsewhere. (And, now I don't know what's
going to happen if I apply a current cvs update either.)

Since this exact distinctive ring is used by a large number of pbx and telco
systems, if * does not handle this properly, Digium is going to either get
one hell of a lot of calls or * is going to have to change to properly
handle it.

Bottom line: the * cvs from about Sep 13 looked for the callerid right after
the first ring stopped, and was not based on telephone "standards" (which
are timer based). Based on recent google searches, it would appear Mark was 
working on some sort of cadence algorithum in early 2002, but I've not 
found any recent reference that would suggest distinctive ringing is 
actually supported in current source in any form whatsoever.