> I'm still trying to examine a DID solution for this customer but
don't
> understand how a single trunk (whatever that is--I assumed just a single > pair of wires like a POTS line, but I'm thinking now it must not be) can > support multiple (incoming) phones calls. As another attempt to help clarify this, I can add that DID is a
service you subscribe to with your local carrier as a range of numbers that are
shared over a smaller number of physical DID trunks brought into your premise by
the carrier. For example, you might buy a block of 50 numbers ranging from
650-555-5200 to 650-555-5249 and subscribe to 5 DID circuits.
A special signalling method over these trunks delivers the actual number
that was dialed (the last 4 digits) to the PBX on each inbound
call. This is not the same as ANI. This is information on the called
number, not the calling number. The PBX then interprets the dialed
number information and rings the proper station. That is a general
description of how the classic DID service works over inband/analog
signalling. Each DID circuit can only handle 1 incoming call at a
time. Pure DID circuits are used only for inbound calls, not
outbound.
Variations on this exist in the digital signalling to support
the same result (ringing a specific phone with 10-digits over shared
trunks). You can do this with ISDN or T1 or Inward 800 service (aka DNIS)
or other means. In some of these cases, the same lines may be used for
2-way traffic (inbound and outbound). None of these are the same
services from the carrier and don't interface with the PBX the same way. They
all have a much different pricing structure ranging from, say, $50/mo per
DID line, to hundreds or thousands per month for T1 or ISDN PRI (24 or 23
channels).
From what I understand of the Digium cards, DID signalling is
not supported.
Hope that helps a bit -- David Schlossman
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- RE: [Asterisk-Users] yet another question on DID trunks Tim Thompson
- Re: [Asterisk-Users] yet another question on DID t... david
- Re: [Asterisk-Users] yet another question on D... Tilghman Lesher
- Re: [Asterisk-Users] yet another question ... Steven Critchfield
- Re: [Asterisk-Users] yet another question ... Eric Wieling