asterisk users - Jan 2004 - RE: Asterisk-Users digest, Vol 1 #2588 - 11 msgs

Message: 5
To: asterisk-users@lists.digium.com
From: Doug Meredith <doug.meredith@skyridge.com>
Date: Wed, 21 Jan 2004 20:05:19 -0400
Organization: Skyridge Systems Inc.
Subject: [Asterisk-Users] Re: What technology could my phone company be
using?
Reply-To: asterisk-users@lists.digium.com
>>Mark Hazlewood <lists@idontknow.com> wrote:
>>Sounds like Centrex services, we had it from Telus in Alberta a few
years
>>ago.
>I believe this is used for Centrex.  I thought Centrex was basically a
>CO-hosted PBX.  Is it also a local-loop technology?  Are there PCI
>cards or SIP gateway boxes available?
You can think of Centrex as a virtual PBX residing within a LEC or CLEC
switch. It gives you most of the functionality of an on premise PBX
delivered over local loops from the LEC or CLEC switch. This allows
three or four digit dialing between extensions and no charges incurred
for calls unless the user dials 9 for an outside line. 

Centrex can use POTS or ISDN desksets or a mixture of both. For
instance, individual users can have POTS desksets but a receptionist
could have an ISDN deskset to provide programmable keys for multiline
answer and transfer. ADSI desksets can also be used to provide this
functionality.

I assume you are questioning the availability of Centrex compatible
hardware for a system that doesn't employ Asterisk, as Centrex would be
redundant when connected to Asterisk. Any voice capable PCI modem card
can be used to terminate a Centrex POTS loop. ADSI capability may exist,
as a "Winmodem" DSP could be programmed to handle voice and ADSI, but
I
haven't seen any applicable drivers/software. ISDN Centrex loops can be
terminated on a PCI ISDN card and software is available to provide voice
functionality. If you want a SIP gateway, you might as well use Asterisk
and non-Centrex loops. There is no sense in duplicating PBX
functionality and paying the monthly Centrex charges.

Regards,
George Bean
Puwaba Technologies