[Asterisk-Users] [OT] Centrex Question

[Rich Adamson]

Brian Capouch wrote:
> I haven't dealt with Centrex for a long time, and one of my customers is 
> being courted heavily by a Sprint salesperson.
> 
> Am I not correct in assuming that each "line" of Centrex corresponds to 
> an "extension" in the PBX world?
> 
> This site has 2 POTS lines and 5 extensions, and they told me that for 
> the same thing they're paying right now (~$40/POTS line) they will be 
> getting two Centrex "lines" that will do the same thing.
> 
> The way I understood it, each of those two Centrex lines is an extension.
> 
> In general, would they still be paying their POTS fees, too?
> 
> Sorry for the noise, but I can't discuss this intelligently with them, 
> and that's hurting me.

Historically, there were two forms of Centrex provided by US telcos. 
Centrex, which was based on a shared pbx typically located on the telco 
promises, and, CO Centrex which was based on the Central Office switch 
with added software features. I'd have to guess the majority of the 
current Centrex implementations are actually CO Centrex now, however I 
did run into a recent case (a college) where Qwest was still using a CO 
based pbx.

Both were tariffed by the telcos with rates that were different then 
normal central office business lines, presumably due to shared 
maintenance costs (and features). (Eg, smoke and mirrors.)

Regardless of which implementation Sprint might be using, from the 
central office perspective, a Centrex line is the same physical thing as 
a pots business line. If your customer has been quoted two Centrex 
lines, its two physical connections (or max two simultaneous calls).

It is possible they might also be providing more then two extension 
numbers using something like distinctive ringing, or, some form of 
subscriber carrier system to mux two extensions over a single line 
(doubt that), or mapping five extension numbers at the CO onto two 
physical Centrex lines.

The more likely case is Sprint is simply displacing your customer's on 
site equipment (presumably a key system) with two lines (with different 
numbers or extensions) and five phones. Nothing more, nothing less.

A Centrex line is the same thing as a pots line from a customer's bill 
perspective. In your case, the bill will only have two Centrex line 
charges (no pots charges), plus any features they happen to be selling 
as optional items. (Optional items are typically voicemail services, 
voicemail LED on their phones, possibly custom calling features, etc, etc.)

Without more info, that's about the best guess you're going to get.