Specifications

VoiceFinder VoIP Gateway Configuration Guide (APOS 2.0) Release Version 3.1
AddPac Technology Co., LTD
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3.10.4.7. dtmf-relay
To specify how an H.323 or Session Initiation Protocol (SIP) gateway relays dual tone
multi-frequency (DTMF) tones between telephony interfaces and an IP network, use the
dtmf-relay command in dial peer voice configuration mode. To remove all signaling options
and send the DTMF tones as part of the audio stream, use the no form of this command.
dtmf relay { h245-alphanumeric }
no dtmf relay
3.10.4.7.1. Syntax
Keyword / Argument Description
h245-alphanumeric (Optional) Forwards DTMF tones by using the
H.245“alphanumeric” User Input Indication method. Supports
tones from 0 to 9, *, #, and from A to D.
3.10.4.7.2. Command Default
No default behavior or values
3.10.4.7.3. Command Modes
Dial peer configuration
3.10.4.7.4. Usage Guidelines
DTMF is the tone generated when you press a button on a touch-tone phone. This tone is
compressed at one end of a call; when the tone is decompressed at the other end, it can become
distorted, depending on the codec used. The DTMF relay feature transports DTMF tones
generated after call establishment out-of-band using either a standard H.323 out-of-band
method.
This command determines the outgoing format of relayed DTMF tone, so the gateway takes the
format automatically.
The principal advantage of the dtmf-relay command is that it sends DTMF tones with greater
fidelity than is possible in-band for most low-bandwidth codec, such as G.729 and G.723.
Without the use of DTMF relay, calls established with low-bandwidth codec may have trouble
accessing automated DTMF-based systems, such as voice mail, menu-based Automatic Call