Incoming calls through SS7 for data modemtransmissions – possible??

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I am not sure where you are and what legal conventions are involved.

Are you saying the Telco (and legal restrictions) say you can’t send calls
to the internet via the AS5300 but you can if Asterisk does it directly?
What is the “logic” in that?

Or are they saying your Telco to Asterisk trunks have to be SS7 controlled?

Or are you concerned about Asterisk handling the TDM to IP conversion in an
adequate manner?

I am not sure/aware myself that Asterisk will do a modem to IP conversion.
I think in your example the AS5300 is doing that.

What is the Telco’s problem in doing what the customer was doing before?

Feel free to correspond directly if you want to.

Cary Fitch


From: href=””>
[] On Behalf Of José Pablo
Méndez Soto
Sent: Wednesday, November 24, 2010 7:31 PM
To: href=””>
Subject: [asterisk-users] Incoming calls through SS7 for data
modemtransmissions – possible??


We are working on implementing a solution for a medium service provider.
They were previously using a Cisco AS5300 gateway with some PRI trunks to
receive modem calls, then route them out the Internet.

The Telco they were buying the trunks to discovered this configuration and
restricted them due to legal conventions, and stated that in order to
continue doing this, they would have to talk SS7 directly.

We are planning on solving this by placing an Asterisk server with some
TE410 cards talking SS7 to Telco, and another 4 ISDN ports talking to the
AS5300 for the dial-up to complete after authenticating against a RADIUS

My questions is: can we use only Asterisk to complete/terminate the dial-up
connection, removing the AS5300 out of the picture?

Current topology to be set-up:
Telco –> SS7 –> TE410P-AsteriskServer –> ISDN –> AS5300 –> Internet

Ideal topology:
Telco –> SS7 –> TE410P-AsteriskServer –> Internet

Some posts talk about zapRAS being able to accomplish this, not quite sure

Sounds like possible:

Sounds like not possible:

Thanks in advance,

José Pablo Méndez

One thought on - Incoming calls through SS7 for data modemtransmissions – possible??

  • Thanks Cary,

    What happens is, the Telco won’t allow the small company to resell the ISDN
    connections, meaning, they bought the trunks and DIDs, then sold dialing
    plans to route incoming calls through the PRIs out the Internet. This is not
    the issue though. We definitely have to migrate to an SS7 capable platform,
    because that is the only way the Telco allows them to resell the dial-up
    connections (not ISDN), and Asterisk is the current bet.

    If we can get Asterisk to pick up those calls via SS7, then authenticate
    them, send them out to the Internet, we would be achieving a %100 usage on
    the Digium cards, because one of them wouldn’t be used to talk to the AS.

    Can Asterisk do this?

    Thanks again,

    *José Pablo Méndez

    href=””> [mailto:
    href=””>] *On Behalf Of *José Pablo Méndez