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MGCP DTMF issues

I have an intermittent issue where users call out to the PSTN and access an autoattendant. From time to time certin auto attendants do not recognize these dialed digits. I have contacted Qwest my PRI provider and they told me that he is fairly certain that it is an EML (Engineering Maintenance Loss) or an AML (Audio Maintenance Loss) mismatch. He explained that in DTMF, these settings determine the audio level. He said that most likely our CCM is sending either too quiet and is not received or too loud and is distorting. He thought we were probably set for too loud. He said that normally- by default, PBX are set at an EML for 0. He said that the proper setting is -3. He said 0 is too loud and -6 is too quiet. He suggested changing this setting to -3.

I have looked around and do not see how to adjust this on my 2811 MGCP gateway or in the CUCM admin page for the gateway.

1 REPLY

Re: MGCP DTMF issues

There are a few bugs that can get you on DTMF:

CSCso87127

CSCsv04751

The first is on gateways before 12.4(15)T8

The second is on phone firmware before 8.4.2

Otherwise, you can adjust your audio levels on the PRI:

To make it 3 dB softer outbound:

voice-port 0/0/0:23

output attenuation 3

You can do this without shutting down service, and the command should take immediately.

hth,

nick

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