User Manual

Configuring Audio Features
317
Methods of Transmitting DTMF Digit
RFC 2833
DTMF digits are transmitted using the RTP Event packets that are sent along with the voice path.
These packets use RFC 2833 format and must have a payload type that matches what the other
end is listening for. The payload type for RTP Event packets is configurable. The default payload
type for RTP Event packets is 101 and the payload type is configurable. The Skype for Business
phones use the configured value to negotiate with the other end during call establishment.
The RTP Event packet contains 4 bytes. The 4 bytes are distributed over several fields denoted as
Event, End bit, R-bit, Volume and Duration. If the End bit is set to 1, the packet contains the end
of the DTMF event. You can configure the sending times of the end RTP Event packet.
Procedure
Configuration changes can be performed using the configuration files or locally.
Configuration File
<y0000000000xx>.cfg
Configure the number of times for
the Skype for Business phone to
send the end RTP Event packet.
Parameter:
features.dtmf.repetition
Local
Web User Interface
Configure the number of times for
the Skype for Business phone to
send the end RTP Event packet.
Navigate to:
http://<phoneIPAddress>/servlet?p
=features-general&q=load
Details of Configuration Parameters:
Parameters
Permitted Values
Default
features.dtmf.repetition
1, 2 or 3
3
Description:
Configures the repetition times for the Skype for Business phone to send the end RTP Event
packet during an active call.
Web User Interface:
Features->General Information->DTMF Repetition
Phone User Interface:
None