Whether can support FAX rate 31200

Unanswered Question
Jan 7th, 2009

i have belowing scenario:


Due to use's fax can support 31200, can this topology can support fax relay to 31200?

I use T38 fax relay

I have this problem too.
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Overall Rating: 5 (1 ratings)
STEFAN CHRISTEN Thu, 01/08/2009 - 04:32

Hi Zhang

T.38 only supports Fax at G3 speeds. But you could use the "fax-relay sg3-to-g3" command to tell the fax machines to train down to G3 speeds.

For SG3 speeds you need to configure "modem pass-through".

Check out the follwing links for further information:





zhangjianping Thu, 01/08/2009 - 06:56

Thanks Stefan, 5 points

Through 'sh mgcp' on ISR, i found 'fax-relay sg3-to-g3' is enable by default.

According to my current configuration, the user's fax machine can train down to 9600 speed. Whereas user hope our ISR can support 31200 speed which can be supported by their fax machines


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