[Asterisk-Users] telco access ?s -- PRI, T1, POTS?

[Steven Critchfield]

On Tue, 2003-11-18 at 11:04, john lawler wrote:
> Hi guys,
> working on designing a larger installation for a customer which will 
> involve ~16 analog handsets that I'll be running through a Rhino 
> Equipment channel bank to a Digium T1.  My question is all about what 
> type of phone service would be recommended for my local provider.
> 
> I purchased a CAC FXO channel bank to interface with a second Digium T1 
> card that I've got, and ran some small scale tests on that which seemed 
> to go fine, and I'm sure this solution would be *sufficient* for the 
> customer, but I know he would like to be able to do DID, which, from 
> conversations w/ SBC in my area, I've discovered requires something 
> other than POTS.  We'll be looking to have roughly 10-12 phone lines for 
> both inbound and outbound (as you'd have in the POTS world), or w/e the 
> PRI, etc. equivalent would be.

> The other main point I should make is that both the customer and myself 
> are interested in a solution where we could, in an emergency, or in the 
> event my configuration of Asterisk is inadequate, switch back over to a 
> situation where we could at least place and receive all calls using the 
> analog handsets.  (E.g., from what I know about this stuff, I suppose I 
> could plug the Rhino FXS channel bank into an incoming T1 line which 
> would then split all the lines into analog which my phones could then 
> plug right into--of course, if I went w/ a straight POTS solution, we 
> could obviously just plug 10-12 of the analog handsets into the lines 
> and at least answer the phones (albeit in a haphazard manner)).

Your wish for DID and the wish to remove asterisk from the loop in case
of failure are going to clash with each other. DID can be delivered via
E&M wink, but this will require a machine on your end that will work
with that signaling. E&M wink basically is like having the telco dial an
extension in your PBX for your caller. 

PRI would not allow you to just swap out to analog phones at all as the
Rhino will not understand the signaling on the 24th channel.

You would be best to get very familiar with this setup, and go with the
frac T1. If you don't feel comfortable deploying yet, then you aren't
ready to deploy. I don't wish to seem mean here, but this is a critical
component of your clients business life and if you can't pull it off,
then you don't have any business experimenting on your customers money.
Read the archives of a similar fellow who had a asterisk system not work
out for his client. 

Right now, I'd say a fair knowledge of the internals of asterisk should
be a requirement for anyone selling asterisk systems into a client site.
This would help you go far in justifying your knowledge level to your
customer. If you could even point to your name in the credits file, this
would be a very good selling point to your clients. If you don't want to
get dirty in the coding, thats fine, but you should be able to debug
sections of the code when you find a problem.

So far I know there are several vendors on this list that have their
names in the credits file, and are active here. If you don't feel you
can go it alone, you would also do well to find one of these vendors and
see if they can be contracted out on a contingency basis to cover what
you don't know.

BTW, I am not a vendor. 

-- 
Steven Critchfield  <critch at basesys.com>