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tomkat's picture
Joined: 2010/01/22
Points: 0

I read alot about the DTMF issues and had something I wanted to share. I'm new and don't understand the functionality very well. I have an HT286 and while trying to make a call requiring DTMF the tone was not being passed. In the configuration i had selected Send DTMF: via RTP (RFC2833) I then reconfigured the box to Send DTMF: in-audio via RTP (RFC2833) via SIP INFO and with all three checked I was able to send tone.

Now with that configuration I tried to send a Fax on a _1NXXNXXXXXX Unrestricted Dial Out (1 trunk) SIP/ExcelFax Excel Fax somehow the 1 was duplicated and although i was stripping the 1 out it still left me dialing 1NXXNXXXXXX which would not go thru. I then reconfigured the device to
Send DTMF: via RTP (RFC2833) only and the extra 1 went away. Was the extra digit being sent via audio from the fax machine? I don't believe it was jitter causing the duplication because i could recreate the senario easily and consistantly. (not a big deal because i will only use the fax trunk for faxing not voice but i would like to understand what is going on as it may help with something else later. I guess i could try to duplicate it with a 9 instead of a 1. Do you think it would send a 91 or a 99? if it is related to jitter i would suspect a 99 if it is a tone from the fax machine i would expect a 91. Or maybe someone knows the answer.