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Command Reference
26
Cisco IOS Release 12.0(7)T
The principal advantage of the dtmf-relay command is that it transmits DTMF tones with greater
fidelity than is possible in-band for most low-bandwidth CODECs, such as G.729 and G.723.
Without the use of DTMF relay, calls established with low-bandwidth CODECs may have trouble
accessing automated DTMF-based systems, such as voice-mail, menu-based ACD systems, and
automated banking systems.
Note The cisco-rtp option of the dtmf-relay command is a proprietary Cisco implementation and
only operates between two Cisco AS5800 universal access servers running Cisco IOS Release
12.0(2)XH, or between Cisco AS5800 universal access servers or Cisco 2600 or 3600 modular
access routers running Cisco IOS Release 12.0(2)XH or later releases. Otherwise, the DTMF relay
feature does not function, and the gateway sends DTMF tones in-band.
Examples
The following example configures DTMF relay with the cisco-rtp option when sending DTMF
tones to dial-peer 103:
5800# configure terminal
5800(config)# dial-peer voice 103 voip
5800(config-dial-peer)# dtmf-relay cisco-rtp
5800(config-dial-peer)# end
5800#
The next example configures the gateway to send DTMF in-band (the default) when sending DTMF
tones to dial-peer 103:
5800# configure terminal
5800(config)# dial-peer voice 103 voip
5800(config-dial-peer)# no dtmf-relay
5800(config-dial-peer)# end
Related Commands
Command Description
codec
Specifies the voice coder rate of speech for a dial peer.