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AS5400 - Possible to terminate voip calls to modems?

Level 1
Level 1

I know it's not necessarily ideal, but is it possible for as5400's to terminate voip calls as modem calls?  Is there a sample configuration for such a setup?

i.e. no T1/ISDN interfaces, just two fastethers, call comes in via SIP/RTP gets answered as a dialup modem, handled via normal ppp/pap login methods.

Thanks much!

3 Replies 3

paolo bevilacqua
Hall of Fame
Hall of Fame

It is not possible because it works poorly if it works at all.

Modems calls must be pure TDM end-to-end.

Please clarify:

Is this considered not possible because the cisco is limited and simply cannot be configured to do this, or is it impossible because the quality of the calls could be lower if the IP network was less than ideal?

Suppose I'm a telco, and I run a softswitch that currently converts from TDM to IP, then transmits the IP (all SIP) over a local gigabit backbone to another switch module, then converts back to TDM and terminates the calls to an AS5400 and in fact the modems connect with a respectable 52000, why not remove one of the conversions so it's TDM to IP over a local gigabit backbone, then directly to the AS5400 as IP, with the public Internet being served on the other Fastethernet interface?

Thanks much!

It is impossible because, as mentioned above, modem needs to go over TDM, and does not work well over VoIP, even on an ideal network.

If you were a telco, you would know that in first place.