Q: Why does PBX/Auto answering machine fail to recognise my key presses?

A: Low quality calls and wrong settings may cause the key press events to fail to be recognized. Please check the following settings:

1. Tone region settings.

Go to “VoIP >> Phone Settings”, click the phone index, and then click “Advanced” button to enter advanced settings. You’ll see some predefined country settings in the list, please choose “Australia” from the list, and then click “OK” to confirm your settings.

2. Please try to change DTMF mode.

Different VoIP service provider (VSP/ITSP)’s SIP server may be compatible with different DTMF settings. Please check the user guide your VSP offered to change this setting.

The default setting for Vigor’s DTMF mode is “InBand”, which can be compatible with most SIP servers. In “InBand” mode, Vigor will not process the key presses event and send them as regular sound.

However, in low quality calls, some sound traffic may be lost, and then the PBX/Auto answering machine will fail to recognize your key presses.

Some VSPs recommend using “OutBand (RFC2833)”, in this mode, router will intercept the keypresses and send them in digital format.

Notice that in “OutBand (RFC2833)” mode, you may need to choose “Payload Type”, the default setting is “101”, however, some VSPs will ask to use “96” as “Payload Type”, you may refer to the user guide your VSP offered.

OutBand mode is much better than InBand mode in low quality calls.

“SIP INFO” is another type of “DTMF Mode”, in this mode; keypresses will be processed and sent in SIP messages. If you fail in both InBand and OutBand mode, try SIP INFO mode.