Missing DTMF digits


We have an application (app) in a non Asterisk system that gets IP calls from an Asterisk system.
The VoIp software we use is Dialogic HMP.
DTMF has to be RFC2833, and codec G711

When end users type DTMF digits, the app is getting less digits that it should :frowning: . This is happening very, very often.

At our side we recorded the DTMF tones, and saw that the gap between tones is 0.006 instead of .040 or more.

Appreciate a hint