Deploying some PolyCom VVX 600’s and Asterisk to power a small office PBX I found that phone users could not use DTMF tones for IVR operations. Such as “Press 1 for sales, 2 for accounting” sort of thing. As you can imagine, this makes navigating an IVR or reaching direct extensions very difficult.
Luckily, the solution was simple. I added the following lines to the configuration file, which the phone downloads from the TFTP server on boot.
<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <!-- Application SIP Helford3 188.8.131.5257 02-Jul-19 06:06 --> <!-- Created 10-04-2020 13:45 --> <!-- Base profile Generic --> <WEB_CONFIG> <OVERRIDES (OTHER CONFIG ENTRIES HERE) voIpProt.SIP.dtmfViaSignaling.rfc2976="0" tone.dtmf.rfc2833Payload="101" /> </WEB_CONFIG>
This should resolve the issue, in my tests this resolved the issue and users were able to operate IVR’s and enter direct extensions.