MobiLink IP
VoIP
MobilinkIP_Usermanual-sw1.2.21_revGen.doc
Page 108 of 188
When you use H323 protocol for VoIP instead of SIP, you can select the option “H.245 alphanumeric”.
The ITU-T H.245 standard specifies several ways of sending out DTMF for the H323 protocol.
In this case, tones are sent out over the H.245 signaling channel, rather than in-band with voice traffic
via RTP channel.
Rohde & Schwarz Topex S.A. has implemented the
alphanumeric version
of the H.245 signal
protocol for better compatibility - all H.323 version 2 compliant systems are required to support the
"h245-alphanumeric" method, while the support for the "h245-signal" method only optional.