No DTMF from Yealink W56H to door intercom

[UweS]

Sorry, if this is a cross posting, I've already asked in the german forum. Please delete if unwanted.

When someone is ringinging at the door intercom (SIP, german manufacturer 'Behnke'), I can speak, and open the door with dialing a '0'. It works fine from the table phones of Yealink, but not from the mobile ones. Crazy, when I'm calling back the door extension from the mobile W56H, it works. Obviously, it seems there is a problem with the codecs. I have changed the order of the codecs in many ways. Also, I have switched through all the DTMF modes for transferring (in band, SIP-Info, RFC2833).
Who can help?

Thank you
Uwe

using latest V 16.0.8.9

 

[JohnS_3CX]

Hi Uwe,

The perhaps when the doorphone is initiating the call it does not specify that it supports RFC2833, hence during one direction it fails, but during the opposite direction it works because the W56H does specify DTMF support.

I think this needs to be analyzed in Wireshark to see what the Behke sends, because it is not a supported device so we are not aware of what it does when it initiates a call.

Please do not post packet captures on the forum, either check them yourself if know how or even better we recommend to contact your 3CX Partner to help your directly.

 

[UweS]

Thanks John. The 'Behnke' also supports different DTMF modes, which I have tried. Our partner has no idea, he also says it's not a supported device.

I will give Wireshark a try.

 

[JohnS_3CX]

If you don't manage to get it working as you want, you may also contact the device manufacturer for help and provide them with your Wireshark captures

We do however have a list of supported doorphones if you consider replacing the current one, models like the Fanvil i30 or Grandstream GDS3710 which provide both audio/video and are fully supported.
https://www.3cx.com/sip-phones/