We have an issue that has started recently with calls going through our digital receptionist not recognising any numbers dialled so it plays through the whole message before transferring to the reception handset.
After further testing we have narrowed it down further to it only affecting iPhones on 4g on one mobile provider network if we drop the mobile connection to 3g it works. If we leave 4g on and turn VoLTE off it works.
If we ring a different SIP trunk they all work.
We have tested with Android on the same network on both 3g and 4g and it works ok.
The network provider has told us the following
"The problem seems to be in the negotiation of codecs. The customer 3CX is replying with a different rate for the audio than they use for the event. In order to have DTMF detected it is mandatory to have both in the same rate."'
Is this possible to change on the 3CX system or are they talking rubbish and I need to go back and escalate to their support team?
Just looked at our settings and the only difference was the Support Reinvites being checked on the SIP trunk options. Removed this and it now works.
After further testing we have narrowed it down further to it only affecting iPhones on 4g on one mobile provider network if we drop the mobile connection to 3g it works. If we leave 4g on and turn VoLTE off it works.
If we ring a different SIP trunk they all work.
We have tested with Android on the same network on both 3g and 4g and it works ok.
The network provider has told us the following
"The problem seems to be in the negotiation of codecs. The customer 3CX is replying with a different rate for the audio than they use for the event. In order to have DTMF detected it is mandatory to have both in the same rate."'
Is this possible to change on the 3CX system or are they talking rubbish and I need to go back and escalate to their support team?
Just looked at our settings and the only difference was the Support Reinvites being checked on the SIP trunk options. Removed this and it now works.
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