VoIP bridge for PBXs


I would like to connect 2 PBXs with VoIP bridge to make calls from POTS phone 1 to POTS phone 2…

POTS phone 1 <—> PBX <—> Asterisk Server <---- VPN ----> Asterisk Server <-----> PBX <----> POTS phone 2

What do I need to install between PBXs and Asterisk Servers and how to configure those servers?

I don’t know much about it myself, but i suspect you’ll have to say what PBXs they are, if you’re going to get a useful response.

I think that it doesn’t matter. I can just setup those PBXs to forward call to Asterisk… but I don’t know what kind of hardware do I need and how to setup Asterisk to handle it.
I just want it to behave like this POTS phone 2 is another internal line for PBX1, and POTS phone 1 is another internal line for PBX2.

Check out the TDM400P cards made by Digium digium.com . You can configure them with up to 4 FXS or FXO ports, or a mixture of the two.

Have a read of this booK:

voip-info.org/wiki/view/Aste … +Telephony

and check out the information on this web site:


and you should have most of the information you need.

Hey… I don’t need RTFM answer. I know about those sites.

What for do I need any FXO? What for 4xFXS? I just want to make point-point connection.

Maybe there is another keyword for my problem (“VoIP bridge” gives me poor search results).

If your PBX can’t speak SIP or IAX (or heaven forbid h323!) you will need fxo interfaces on both asterisk servers. That’s why the question about what PBX you are using.

And some more info on your PBXs would still come in handy:

Depending on the interfaces provided by your PBXs to talk to anything else you will need the appropriate interfaces on the Asterisk boxes.

I.e. if your PBX provides a PRI (T1 or E1) interface, you’ll need a corresponding interface on the Asterisk; if it provides BRI ISDN interfaces, you’ll need a BRI ISDN interface on the Asterisk box. If you want to use a normal (analog POTS) FXO interface on the PBX, you need a FXS interface on the Asterisk; if you want to use an analog (POTS) extension interface on the PBX, you’ll need an FXO on the Asterisk.

Now, since you didn’t seem to realize that this information is absolutely essential to anyone wanting to answer your original question, it was not so inappropriate to give you an RTFM answer – you might have found that out from reading the recommended sites.

And these sites will also tell you what is available for Asterisk for each of the above mentioned interface types, so I will repeat WillKemp’s recommendation that you go read especialy voip-info.org/wiki/view/Asterisk and the hardware sections there.

Those are old and simple FXO/FXS PBXs… (i thought that my diagram with POTS phones explains that :stuck_out_tongue_winking_eye: )… the problem is … do I need FXO and FXS on each asterisk server or just something … cheaper?

Thanks! … and that is what I want to know.