[asterisk-users] Re: how to define a pilot number

[Eric "ManxPower" Wieling]

Lee Jenkins wrote:
> Lito Lampitoc wrote:
>> thanks for enlightening. So you mean, if I have 3 lines when the 
>> caller dialled the first line and it was busy, the call will be 
>> diverted to the next two available lines in random?
>>
> 
> I don't think it's random.  I think its just sequential.  If main line 
> is busy, try second.  If that is unavailable, then try third in 
> sequence, etc.
> 
> It's called "rollover" here.
> 

It is also called a "hunt group".  The telco will usually roll the call 
the the next available line in the huntgroup.  However they can also 
roll to the "longest idle" line.  This can help in modem pools where if 
a modem connected to the 2nd (or whatever) line of the hunt group dies 
then the line won't be busy and the call won't roll over.  "longest 
idle" can at least let most callers get thru in the event of a failure 
on one of the modems.

When dealing with analog lines you have to be concerned about "glare". 
Glare happens when the PBX picks up a line at the exact moement the 
telco sends a call to the line.  One way to do this is to have the PBX 
hunt from the top of the hunt group and work its way down, and have the 
telco hunt from the bottom up.