Hi Paolo,
In CME, under ephone and ephone-template configuration, there is a
command to lengthen the dtmf duration from the default to 200ms
(max). The CLI command is nte-end-digit-delay.
.
Note that the max is 200ms.
You will also need the
CME-CUE-28#conf t
CME-CUE-28(config)# voice service voip
CME-CUE-28(config-voi-serv)# dtmf-interworking rtp-nte
then
CME-CUE-28(config-ephone)#nte-end-digit-delay 200
You need to configure both voice service dtmf-interworking rtp-nte and the
nte command on the ephone/ephone-template in question to produce the
necessary delay on the end packet.
Please note this command was introduced in 12.4(15) and rolled into 12.4(20).