This command takes the specified live-feed audio stream and uses it
as MOH for a Cisco Unified CME system. The connection for the live-feed audio
stream is established as an automatically connected voice call. If the
out-call keyword is used, the type of
connection can include VoIP calls if voice activity detection (VAD) is
disabled. The typical operation is for the MOH ephone-dn to establish a call to
a local router E&M voice port.
Connection via E&M is the recommended mechanism because it
requires minimal external components. The E&M port must be placed in 4-wire
operation, using E&M immediate signaling and with the
auto-cut-through option enabled. You directly
connect a line-level audio feed (standard audio jack) to pins 3 and 6 of an
E&M RJ-45 connector. The E&M WAN interface card (WIC) has a built-in
audio transformer that provides appropriate electrical isolation for the
external audio source. (The audio connection on the E&M port does not
require loop current.) The
auto-cut-through commands disable E&M
signaling on this voice port. A G.711 audio packet stream is generated by the
digital signal processor (DSP) on the E&M port.
If you are using an FXO voice port for live-feed MOH instead of an
E&M port, connect the MOH source to the FXO voice port. This connection
requires an external adapter to supply normal telephone company (telco) battery
voltage with the correct polarity to the tip-and-ring leads of the FXO port.
The adapter must also provide transformer-based isolation between the external
audio source and the tip-and-ring leads of the FXO port.
Music from a live feed is continuously fed into the MOH playout
buffer instead of being read from an audio file in flash memory. There is
typically a two-second delay with live-feed MOH.
out-call keyword is used, an outbound call to
the MOH live-feed source is attempted (or reattempted) every 30 seconds until
the call is connected to the ephone-dn (extension) that has been configured for
MOH. Note that this ephone-dn is not associated with any physical phone.
moh (ephone-dn) command is used without any
keywords or arguments, the ephone-dn will accept an incoming call and use the
audio stream from the call as the source for the MOH stream, displacing any
audio stream that is available from a flash file. To accept an incoming call,
the ephone-dn must have an extension or phone number configured for it. A
typical usage would be for an external H.323-based server device to call the
ephone-dn to deliver an audio stream to the Cisco CME system. Normally, only a
single ephone-dn would be configured like this. If there is more than one
ephone configured to accept incoming calls for MOH, the first ephone-dn that is
successfully connected to a call (incoming or outgoing) is the MOH source for
MOH can also be derived from an audio file when you use the
moh command in telephony-service
configuration mode with the
filename argument. There can be only one MOH stream at a time in
a Cisco CME system, and if both an audio file and a live feed have been
specified for the MOH stream, the router seeks the live feed from the
(ephone-dn) command first. If the live feed is
found, the router displaces the audio file source. If the live feed is not
found or fails at any time, the router falls back to the audio file source that
was specified in the
If you use the
ip keyword to specify a multicast address in
this command, the audio stream is sent to the multicast address in addition to
serving as the MOH source. Additionally, if you specify a different multicast
address using the
moh command under telephony-service configuration
mode, the audio stream is also sent to the multicast address that you named in
that command. It is therefore possible to send the live-feed audio stream to
MOH and to two different multicast addresses: the one that is directly
configured under the
(ephone-dn) command and the one that is indirectly
configured under the
moh (telephony-service) command.
A related command, the
feed command, provides the ability to
multicast an audio stream that is not the MOH audio stream.
IP phones do not support multicast at 224.x.x.x addresses.