Channel bank between analog PBX and PSTN?


#1

One of my customers has asked me to augment their extremely outdated phone system such that they can do better call handling. They want to create tone menuing with which callers can be directed to the appropriate party, a recorded message…you get the idea. They don’t know it yet but I’m envisioning ways in which I can facilitate telecommuting, call monitoring for training purposes, etc. Of course I told them Asterisk was the way to go. I’m a full-time software engineer and am pretty confident I’ll be able to get Asterisk to sing the right tune, but I’m a bit shaky on the analog hook-up part.

They are very interested in seeing the Asterisk solution. The trouble is: I can’t spend a whole bunch of money on new hard-phones right at the beginning. They presently have a circa-1995 Panasonic setup (KX-TD1232) inside an extremely old building with no modern network wiring to speak of (nor conduit to pull it through). Their antique wiring barely accommodates their 32 extensions. So, I’ve cooked up a kludge that I think will tie them over until newer infrastructure can be installed.

I’ve purchased an Adtran 750 with 2 FXO and 3 FXS modules. I’m hoping to combine it with a TE110P and patch it in between their KSU and the 8 CO lines they have coming into the building. Their KSU can have 4 more CO connections added that I’ll hook up to the remaining four FXS channels.

I’ve read this but I’m going in a bit deeper than SirBryan did and am hoping for a few more pointers.

Let me know if you’ve tried this and the pitfalls you ran into. If you have any further suggestions they’ll be helpful, too.


#2

Well, Masterquestion ahead:

Are you really sure you want to bother with a lot of Sipura ATA’s ?

They are a little bitchi to configure and get them work with asterisk hasslefree.

For 30 phones, you need 10 X 3 Port Sipura ATA’s + Faxlines etc.

I would REALLY and SERIOUSLY ask them to make “nails with heads” - like we say here (opposite to “nor fish nor flesh”).

The full power of asterisk comes through, when the phones are able to do more then just ring ring…

And the echo with handsets (high “comfort noise”) is not what i would call a “good argument” to change.

See, a SNOM 360 phone (hard SIP phone with many features) is about 190,- € here.

If you say (order a few for backup)
35 X 190 = 6650,-

Say you need 1000,- spare (handsets for boss, ATA’s, cabling, router etc)
and a server (asterisk in that size will do good on a 700,- machine)
you are about 8,5 K €.

That is (leasing) about 250,- € / month for 3 years.
I would REALLY suggest to do this !

I mean, its up to you, but i would reject a job like that, to bother with antique phones in the age of 10 yrs+ … ugh !


#3

Thanks Richard.

Maybe I’m missing something, but I’m not sure why I need any Sipura ATAs? I thought I could use the FXS ports on my channel bank. Please explain.


#4

How do you connect the old Panasonic phones to asterisk ?


#5

I think he is planning on Asterisk between the PBX and the CO. I think it should be doable but no nothing about the Panasonic.


#6

Rusty is correct. I don’t plan to take the PBX out. As far as the PBX is concerned, it will think Asterisk is the CO. I plan to trigger its touch tone features from my dialplan.

See any issues?


#7

Can I assume that since no one has posted anything saying the FXO/FXS connections I’m proposing to make will be a problem that they won’t be?


#8

I have to admit that this “hybrid setups” are not my playground - i even dont like them. Its a bit like buying a porsche to put it on the tow-bar of a volkswagen, well…imho.

It begins already with the fact, that you need to close every dialstring with the poundkey or you need to wait 4 seconds for the standard dial-timeout, so asteriskis making the dial. Well, thats just me.

But that doesnt mean you can do it and work without problems with a setup like this.