We have 25 D385 Deskphones and 17 M70 Dect with M900.

We also have several doors they are connected trough phonelines to our PBX. To open the door we have to send "#988" while in a call from the phone for example. The M70 sends DTMF tones, the D385 doesn't.

I tried the Settings "DTMF via SIP-INFO" to ON but without success. Also i switched RTP-Audio-Encryption to OFF, "Long SDP Answer" to ON and choose only these codecs "g722,pcma,pcmu,telephone-event". Nothing helped.

We have a IVR on our PBX, so i can test both phones. From Dect i can choose an option, from D385 not.

D385 Firmware is 10.1.169.13

What i'm doing wrong?

Regards.