Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

MODEM 'NSE' and 'REQUEST MODE' - H323 sw Version 12.4

Cisco 2611 and 2811. Call scenario MGW1-to-Cisco 2811.

Call type: MODEM call and configuration=

#modem passthrough nse codec g711alaw

Original G729 codec is in band negotiated to G711 thanks to the above command (using RTP payload Type 100). However with other H323 MGWs not supporting NSE, the REQUEST MODE procedure should be used to negotiate the G711 and start modem. However it looks like Cisco 12.4 does not support this procedure for MODEM (for FAX passtrough RequestMode is supported). Does anyone know how force RequestMode for MODEM calls?.thanks


Re: MODEM 'NSE' and 'REQUEST MODE' - H323 sw Version 12.4

You can configure fax pass-through for modems. The only difference between fax passthrough and modem passthrough configuration is what they are kicked off of on. If the other side is already kicking it off, it shouldn't be a problem.

Try adding this configuration:

voice service voip

fax protocol pass-through g711ulaw