Upon reception of a DTMF digit from the end user, the Cisco H.323 MGW configured in out of band signal mode sends a User Input Indication (UII) signal message, with a length of 4s:
h245Control: 1 item
Item 0
Item: 14 octets
H.245
PDU Type: indication (3)
indication: userInput (13)
userInput: signal (3)
signal
signalType: 1
duration: 4000
rtp
timestamp: 4001535283
logicalChannelNumber: 1
When the end user releases digit key, the MGW sends a UII signalUpdate message to update the DTMF duration to the actual duration (here 125 ms):
h245Control: 1 item
Item 0
Item: 9 octets
H.245
PDU Type: indication (3)
indication: userInput (13)
userInput: signalUpdate (4)
signalUpdate
duration: 125
rtp
logicalChannelNumber: 1
This behavior is not a fault technically, but it causes problems with some equipments that do not recognize well the UII signalUpdate message.
I'm using IOS 5300 Software (C5300-IK8S-M), Version 12.2(15)T14.
Is this behavior still the same is more recent versions, or is it possible to change this behavior as follows:
1?) Send the signal message with a fixed duration much lower than 4s (typically around 100 ms), or
2?) Send the signal message ony when the DTMF duration is known (hence avoiding the signalUpdate)?
