Yealink VC800 Administrator's Manual

Also see for MeetingSpace VC500: Administrator's guide Administrator's guide Administrator's guide Administrator's guide Quick configuration guide

Administrator’s Guide for Yealink VC800&VC500 Video Conferencing System96For more information on how to use refer toYealink VC800&VC500 Full HD Video ConferencingSystem User Guide.DTMFDTMF (Dual Tone Multi-frequency), better known as touch-tone, is used for telecommunicationsignaling over analog telephone lines in the voice-frequency band. DTMF is the signal sent fromthe IP phone to the network, which is generated when pressing the keypad during a call. Eachkey pressed on the IP phone generates one sinusoidal tone of two frequencies. One isgenerated from a high frequency group and the other from a low frequency group.The DTMF keypad is laid out in a 4×4 matrix, with each row representing a low frequency, andeach column representing a high frequency. Pressing a digit key (such as '1') will generate asinusoidal tone for each of two frequencies (697 and 1209 hertz (Hz)).DTMF Keypad Frequencies:1209 Hz 1336 Hz 1477 Hz 1633 Hz697 Hz 1 2 3 A770 Hz 4 5 6 B852 Hz 7 8 9 C941 Hz * 0 # DMethods of Transmitting DTMF DigitThree methods of transmitting DTMF digits on SIP calls: RFC 2833 -- DTMF digits are transmitted by RTP Events compliant to RFC 2833. INBAND -- DTMF digits are transmitted in the voice band. SIP INFO -- DTMF digits are transmitted by SIP INFO messages.The method of transmitting DTMF digits is configurable on a per-line basis.RFC 2833DTMF 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 otherend is listening for. The default payload type for RTP Event packets is 101 and the payload typeis configurable. The VC800/VC500 uses the configured value to negotiate with the other endduring call establishment.The RTP Event packet contains 4 bytes. The 4 bytes are distributed over several fields denoted asEvent, End bit, R-bit, Volume and Duration. If the End bit is set to 1, the packet contains the endof the DTMF event. You can configure the sending times of the end RTP Event packet.