This document answers some of the primary questions about Music On Hold
(MoH) in Cisco CallManager 3.x/4.x/5.x and 6.x. Refer to
CallManager Administration and System Guides and the
Notes for Cisco CallManager Releases for more information. Refer to
Communications Manager (CallManager) Frequently Asked Questions for more
informatio on the latest versions.
This list of possible symptoms might be encountered when you attempt to
start the IP Voice Media Streaming App (CallManager Serviceability > Tools
> Service Activation) which is required to configure the MoH service:
The The following Services are not properly configured
on the service configuration page error message is reported
when you attempt to start or activate IP Voice Media Streaming App. The service
that was not configured correctly was the IP Voice Media Streaming App.
The web page displays a message that it was actually disabling the
service when you attempt to activate the IP Voice Media Streaming App service.
Manually remove these entries to resolve these symptoms:
After you remove these three entries, the IP Voice Media Streaming App
should activate successfully. After you activate the IP Voice Media Streaming
App, make sure that you have an entry in the MoH servers, MTP and Conference
bridge configuration pages.
What is Music On Hold?
A. MoH, an application that can be installed to a media convergence server
(MCS), streams Real-Time Protocol (RTP) audio in either unicast or multicast
streams from the application server to the endpoint device.
Administrators can stream MoH audio to all Cisco IP phones, Cisco Voice
over IP (VoIP) gateways, and Cisco IP SoftPhone. Endpoint devices that support
receiving multicast for MoH include Cisco IP Phone models 7910, 7940, 7960,
Cisco Catalyst 4000 Access Gateway Module (AGM) gateways, Catalyst 4224
gateways, and VG200 gateways.
A dedicated MCS server can stream as many as 250 MoH streams (unicast
or multicast). Any server can stream from up to 50 separate logical sources,
each with its own continuously looping source .wav file. A 51st source—a sound
card—can provide a real-time streaming source. Audio codec formats for any
stream include G.711, G.729A, and high-fidelity audio. A translation utility
included with the application allows translation from common formats such as
.mp3 to the supported audio codecs.
Which version of Cisco CallManager supports Music On Hold?
A. MoH is supported in Cisco CallManager version 3.x, 4.x, and
On what servers is Music On Hold deployed?
A. MoH servers are deployed on any media convergence server (MCS)
platform. This could be a stand alone MoH server on an MCS platform or an MoH
service that is co-located with the Cisco CallManager.
What are the current capabilities of Music On Hold?
A. The current capabilities and features of MoH include:
MoH multicast and unicast streaming service
Music streaming service for "user" hold and "network" hold
51 sources per media convergence server (MCS)
Fifty continuously looping .wav file sources
One real-time streaming source
Each source configurable as either unicast or multi-cast
Support for audio streaming to selected devices
Gateways (multicast only):
6608—Not until Seaview 3.3
VG200 (H.323)—Yes with Cisco IOS® Software Release 12.2(11)T and
later, enable the ccm-manager music-on-hold
VG200 (MGCP)—Yes, same as VG200 (H.323)
Gateways (unicast only)—AT-2/-4/-8, AS-2/-4/-8, and all other Cisco
IOS® VoIP gateways, including Cisco 1750, 2600/3600, 5300, 58xx, and 72xx
Cisco IP phones (unicast, multicast)—7910, 7940, and 7960
Cisco IP phones (unicast only)—Cisco 7935, 12 SP+, and 30 VIP phones
Cisco IP SoftPhone (unicast only)
Maximum 250 simultaneous on-hold streaming sessions per
Multiple server instances for application scalability
Multiple server instances for server load balancing and redundancy
G.711, G.729A, and wide-band audio codec support
Off-line audio translation utility
How do I make the Music on Hold (MOH) as a ringback tone when using Cisco
CallManager with IPCC?
A. When an ICD call rings an agent, the caller is put on hold by the
CallManager. At this point, the CallManager MOH can be used to play a ringback
tone to the ICD caller while waiting for the Agent to answer the phone. In
order to set this up, you need to configure all the CTI ports Network
Hold Audio Source as the wav file (ringback.wav) you
want to play during the consult transfer.
Note: Make sure that the ringback.wav file is in the CallManager server and
configured appropriately. Otherwise this can cause CPU spiking in Cisco
Why are remote sites that use Locations-Based Admission Control unable to
receive Music On Hold in the initial release of Cisco CallManager 3.x and 4.x?
A. If you use Locations-Based Call Admission Control, users at remote
sites (for example, across a WAN link) cannot use MoH. Remote site users cannot
use this feature because bandwidth calculations across location boundaries do
not take into account MoH streams. In place of MoH, these users receive Tone on
Hold (ToH), and bandwidth calculations are then correct.
How does Music On Hold work after the Cisco CallManager 3.x and 4.x
A. After the Cisco CallManager 3.1 maintenance release and later, MoH is
part of the Locations-Based Bandwidth Calculation. Remote sites are able to
receive a MoH stream if there is bandwidth available. If there is not enough
bandwidth for the stream, then the user receives Tone on Hold (ToH).
Do I need to have a sound card?
A. Not necessarily. A sound card is only needed if you intend to use a
fixed audio source, such as a CD-ROM or sound input, such as live radio.
Otherwise, the MoH server streams the local .wav files that are on its own hard
What sound cards can be used with the Music On Hold server?
A. The media convergence servers (MCSs) do not ship with sound cards. If
you choose to use a sound card, you need to purchase it separately. The Sound
Blaster protocol control information (PCI) 16 sound card has been tested and is
recommended for use with the Cisco MCS 7835 and MCS 7835-1000. The Cisco
MCS7825-800 requires a PCI 2.2 card. Therefore, no recommended or supported
sound card exists for this server model.
What is a Cisco MoH USB audio sound card
A. The Cisco MoH USB audio sound card (MOH-USB-AUDIO=) can be used for the
connection of a fixed or live audio source to the MoH server through the USB
port. This USB sound card is only compatible with MCS platforms that support
Cisco Unified CM Release 5.x and 6.x that run on Linux Server.
How many unicast streams can a stand-alone Music On Hold server support?
A. A stand-alone MoH server can support up to 250 unicast streams.
How many unicast streams can be supported on a co-located server?
A. The maximum number of unicast streams is 30 for a co-located
When do I need a stand-alone Music On Hold server?
A. In general, you can safely assume that 1 percent of the user community
is on hold at any one time. (Some Enterprise deployments can require more.)
Therefore, it is essential to have at least that many available streams. If,
for instance, you had 1,000 phones in a cluster, you would need approximately
ten MoH streams available to service these calls.
You can load-share across your cluster with a Media Resource List /
Media Resource Groups. For instance, if you have four co-located Cisco
CallManager / MoH servers, you can have 25 percent of your users use Cisco
CallManager / MoH A, 25 percent using Cisco CallManager / MoH B. When you do
this, you can have up to 120 unicast streams across the cluster.
If a similar load-sharing design does not provide the number of unicast
streams that are needed, then a stand-alone server can be implemented.
If I have co-located a Music On Hold Server, how do I make sure that I do
not exceed 30 unicast streams?
A. On the MoH Servers Configuration page, you can specify the number of
unicast streams to allow. In the Maximum Half Duplex Streams field, enter
30 and click Update. Also, the thirty-first
call is still placed on hold but only receives Tone On Hold (ToH).
What happens if I run out of streams?
A. If you specify thirty unicast streams, and a thirty-first caller is
placed on hold, that caller now receives Tone on Hold.
What codecs are supported for Music On Hold?
A. The Cisco IP Voice Media Stream application can be enabled to stream
G.711u-law, G.711a-law, G.729, and Wideband. G.711 is the only codec enabled by
default. Additional codecs can be selected under Service > Service
Parameters > <select your server> > Cisco IP
Voice Media Streaming Application.
How can I configure Music on Hold to use G.711 while voice calls use
A. Refer to
MoH uses G.711 Codec while Voice Calls use G.729 Codec Configuration
Why do users hear a beep sound (Tone on Hold) instead of Music on
A. Cisco CallManager checks these settings in order to play MoH to the
MoH configuration in Line settings
MoH configuration in Phone settings
MoH configuration in Device Pool settings
Note: With Cisco CallManager 4.2, the Network Hold MoH Audio Source and
User Hold MoH Audio Source is moved under
Profile Configuration instead of Device Pool Configuration. In other
words, with Cisco CallManager 4.2, the different locations to configure the
audio source are:
Directory Number Level.
Common Profile Level.
The DN/Line level takes the highest priority and
the Common Profile takes the lowest
If all of these settings have a value of None for
MoH fields, then Cisco CallManager takes the values configured in the Cisco
CallManager Service Parameters page.
Go to Cisco CallManager administration page. Choose the
Service menu and choose Service
Choose the Cisco CallManager server and choose the Cisco
Make sure the MoH parameters are configured with valid
Restart the Cisco IP Voice Media Streaming App
service in the Control Center.
Another reason is a mismatch between the codec configuration used by
the MoH server and the region in which the endpoint is registered. For example,
the MoH server advertises only a capability of G.711 mu-law. If an endpoint is
in another region that enforces the G.729 codec, the Cisco CallManager chooses
Tone On Hold (ToH) because a stream cannot be played to this endpoint. Try to
add additional codecs for MoH in Cisco IP Voice Media Streaming App service
Go to Cisco CallManager administration page. Choose the
Service menu and choose Service
Select the Cisco CallManager server and select the Cisco IP
Voice Media Streaming App service.
Choose additional codecs for MoH. Use Ctrl in
order to select multiple values.
Restart the Cisco IP Voice Media Streaming App service as indicated
in step 5.
If location-based connection admission control is used and there is
no bandwidth available, then Cisco CallManager sends ToH rather than
If Media Resource Groups are used, ensure that the MoH server is part
of the Media Resource Group and that the group belongs to a Media Resource
List. Also check that your Cisco IP Phone belongs to the Media Resource
Check the MoH server registration status. Check the Run Flag under
the MoH Server Configuration page, and ensure it is set to
ToH can be played if there are no available audio streams. This is
because the MoH server has a finite number of unicast streams it can generate.
If this limit is exceeded, is causes Cisco CallManager to play ToH. Check
PerfMon or the Real-Time Monitoring Tool to see if streams are
Ensure that the MoH server has connectivity to the held
If multicast MoH is used, verify that the multicast stream makes it
to the network of the endpoint that needs to hear it. It could be that the
infrastructure devices, such as routers and switches, no longer forward this
multicast stream. A sniffer is the easiest way to verify that the multicast
stream has made it to the subnet of the Cisco IP phone. Also, if it is a
gateway, ensure that it is multicast-capable for
How do I restart the MoH service that runs on Cisco
A. Complete these steps:
Go to the Cisco CallManager Administration page and choose
Application > Cisco CallManager Serviceability > Tools >
Choose the Cisco CallManager server.
Click the Cisco IP Voice Media Streaming App
radio button under NT service.
This restarts the MoH service in Cisco CallManager.
How do I disable Music on Hold for conference
A. In Cisco CallManager, you can configure MoH so that callers hear music
when one of your users places a call on hold. This can be disruptive if a user
places a conference call on hold. The music, and possible announcements, can
prevent other callers on the conference call from continuing the call until the
user who placed the call on hold returns to the call.
You can disable MoH for conference calls when you create a Media
Resource Group in Cisco CallManager for all MoH resources, and add all phones
for which you want to enable MoH to the Resource Group List with the group.
This disables MoH for callers within the same Cisco CallManager cluster, but
does not disable MoH for outside callers.
This procedure shows how to create a new Media Resource Group for MoH
Choose Service > Media Resource > Media Resource
Group from the Cisco CallManager administration page. Cisco
CallManager opens the Media Resource Group Configuration
Enter this information:
Media Resource Group Name—The name of the group.
For example, MoHGroup.
Devices for this Group—Choose all of the MoH
servers in the available resources list and click the down arrow in order to
add them to the selected resources list.
Click Insert. Cisco CallManager adds the
Select Service > Media Resource > Media Resource
Group List. Cisco CallManager opens the Media Resource Group List
Enter this information:
Media Resource Group List Name—The name of the
resource group list. For example,
Media Resource Groups for this List—Choose the
MoH resource group you just created (MoHGroup) in the
available Media Resource Group List and click the down arrow to add them to the
selected Media Resource Group List.
Click Insert. Cisco CallManager adds the group
Configure all phones for which you want to support MoH to use the
Media Resource Group list you just created (MoHGroupList).
You can use the BAT tool to reconfigure many phones at
Why does the IP Media Streaming service cause high CPU
A. The high CPU utilization by the IP Media Streaming service
(IPVMSAPP.exe) can be caused by the MoH audio sources. If the audio files are
either corrupted or empty (zero-length audio), and are configured as audio
sources, they cause high CPU utilization. Refer to the
Audio Sources section of
CallManager Features and Services Guide - Music on Hold in order to
create valid audio source files.
Why is multicast MoH not heard across WAN links or to external
Verify that the multicast stream makes it to the network of the
endpoint that needs to hear it. It could be that the infrastructure devices,
such as routers and switches, no longer forward this multicast stream. A
sniffer is the easiest way to verify that the multicast stream has made it to
the subnet of the Cisco IP phone. Also, if it is a gateway, ensure that it is
multicast-capable for voice.
Increase the hop count on the MoH source file in the MoH Server
Note: In most environments it is recommended to increment multicast based
on the IP address instead of the port. When the IP address is used, a different
multicast IP address is used for each codec that has been configured. When the
port is used, all codecs are sent to all phones on different ports. This can
result in unnecessary network saturation.
How to disable Music on Hold?
A. Set the Run Flag to NO on all of the available MoH
servers to disable MoH for all users. This prevents MoH from being played from
any of the servers in the cluster. Go to the Cisco CallManager Administration
page and choose Service > Media Resource > Music on Hold
Server in order to do this.
In order to disable MoH for one user or a group of users, you need to
create a silent/blank audio source file and assign it to the phone associated
with the user or to the device pool of the devices for which you need to
disable MoH. You can use a sound recorder to create the blank file, and do the
recording without the microphone turned on.
Once you have the file, complete these steps to assign the file to the
device for which you need to disable MoH.
For Cisco CallManager 3.x, copy the blank .wav file to
C:\cisco\dropMOHaudiofileshere\ in the Cisco CallManager
For Cisco CallManager 4.x, copy the blank .wav file to
Open the Cisco CallManager Administration page and choose
Service > Media Resource > Music On Hold Audio
Pick a number not in use for MoH Audio Stream
Choose the blank file you have created for MoH Audio Source File*.
Check Play continuously (repeat) for this
Click Insert and Update.
Choose Service > Service Parameters > Cisco CallManager
> Default Network Hold MoH Audio Source ID and make sure it has the
same number as the MoH Audio Stream Number from step 3.
Select Device > Phone and pick the phone
associated with the user. Make sure the phone is set to the same device pool as
the MoH server. Set the User Hold Audio Source and
Network Hold Audio Source to the new file that you have
Note: In order to disable MoH for a group of users/devices, you need to
assign the blank file to the device pool of the devices for which you need to
disable MoH. Choose System > Device Pool, choose the Device
Pool for the required devices, and set the User Hold Audio Source and Network
Hold Audio Source to the new file that you have created.
Click Update and Reset on the phone
for the changes to take effect.
Make sure that you reset the MoH server and IP Voice Media Streaming
Note: Make sure the audio source file is silent and not empty or zero
length, as these files can cause high CPU usage. See the Why does the IP Media Streaming service cause high CPU
utilization? section for more information.
Note: Complete these steps in order to disable MoH for one user or a group
Define a Media Resource Group (MRG) without any MoH resources, and
put that group into a Media Resource Group List (MRGL) for the users that you
want to deny MoH access.
Put the MoH resource into an MRG, and put that group into an MRGL
for the users that you want to permit MoH access.
How do I disable Tone on Hold (ToH)?
A. Complete these steps in order to disable ToH:
Go to the Cisco CallManager Administration
Choose Service > Service
Choose CallManager IP as the Server and Cisco
CallManager as the Service.
Go to the Clusterwide Parameters (Device -
General) section on the Service Parameters configuration
Change the value of the Tone On Hold Timer to 2000000
seconds and click Update.
This parameter specifies the number of seconds between every two hold
tones that are played when a call is put on hold. For non-MGCP-based devices,
if this value is 0, the held device plays the hold tone only one time when the
caller is put on hold. If the value is 200000, no hold tone plays. Otherwise,
the held device plays the hold tone every so many seconds (specified by this
value) repeatedly. If the specified value is less than 5 seconds, the device
raises it to 5 seconds. For MGCP-based devices, the hold tone is disabled if
this value is 0 or 200000. Any other value enables the hold tone on MGCP-based
devices when the caller is put on hold.
How do I troubleshoot the issue of tone on hold not playing and I hear
complete silence when the call is put on hold in spite of the fact that tone on
hold is enabled?
A. In order to resolve this issue, choose the CallManager
Service Parameters Configuration page at Service >
Service Parameters > CallManager, and set the Send H225
User Info Message parameter to User Info for Call Progress
Why are calls disconnected a few seconds after a call is placed on
A. This issue can occur when the voice codec for a given device, as
defined by its region, is not in the list of codecs supported by the server
that streams the MoH stream. For example, if a particular device is set to only
use the G.729 codec, but the MoH service is only configured to stream G.711
μ-law, then this particular problem can occur.
Enable G.729 in the IP Voice Media Stream App and
restart the IP Voice Media Stream App service to resolve this issue.
Complete these steps:
Select Service > Service
Parameters and choose Cisco IP Voice Media Streaming App
from the Service pull-down menu.
Under Clusterwide Parameters, select G.729 codec
for Supported MoH Codecs.
Select IP Voice Media Stream App under
Application > Cisco CallManager
Serviceability > Tools > Control
Center and click Restart to restart the IP Voice
Media Stream App Service.
How do I adjust the volume of the MoH audio source on Cisco
A. The volume of a custom-created MoH source is defined by a Cisco
CallManager service parameter and occurs when you create the audio source using
the Cisco MoH Audio Translator service. You must modify the service parameter
and then re-translate the audio source in order to adjust the volume of the MoH
Complete these steps to modify the service parameter that affects MoH
audio source volume.
Open up the Cisco CallManager Admin web page in Internet
Select Service > Service
Select a Cisco CallManager server from the Server drop-down box.
The parameter you change affects all Cisco CallManager servers in
the cluster, so it does not matter which server you select.
Select Cisco MoH Audio Translator on the Service
Click Advanced to see all service parameters.
The Default MoH volume level is the parameter you can change.
The default is -24 and the volume is measured
in decibels (dB). You can enter a value in the range of
-48 (soft) to 0 (loudest), but the
change in volume affects only audio files processed after the change. For
example, change to -28 for a softer source, or -20 for a louder source.
The service parameters setting works only for MoH audio files as the
audio source. If you use a live feed or USB device as the audio source, you
need to complete these steps to reduce the MoH volume.
Select Start > Settings >
Click Sounds and Multimedia.
Go to the Audio tab.
Under Sound Recording, click Volume to adjust the
volume. The changes should take effect immediately after you click
How do you set up the MoH Live-Feed on Survivable Remote Site Telephony
A. For information on how to set up an MoH Live-Feed on SRST gateways,
SRST MoH Live-Feed Support.
Note: SRST MoH Live-Feed is currently not supported with Session Initiation
Protocol (SIP) gateways. It is supported only on H.323 and MGCP gateways.
How do you apply the MOH globally in the Cisco
A. Choose Service > Service Parameters > Cisco Call Manager
> Default Network Hold MOH Audio Source ID in order to apply the
MOH audio stream globally for all the devices.
How to configure Cisco CallManager to make MOH play the music files
A. Complete these steps in order to configure Music on Hold (MOH) to play
Choose Service > Media Resource >Music on Hold Audio
On the MOH Audio Source Configuration, choose the Audio Source file
you want to use and check the Play Continuously (repeat) check
Restart the Cisco Media Streaming Application service and the MOH
server, after you update the configuration page for that file.