The integrated Music on Hold feature allows users to place on-net and off-net users on hold with music that is streamed from a streaming source. This source makes music available to any possible on-net or off-net device that is placed on hold. On-net devices include station devices and applications that are placed on hold, consult hold, or park hold by an interactive voice response or call distributor. Off-net users include those who are connected through Media Gateway Control Protocol or skinny gateways. The Music on Hold feature is also available for IP POTS phones that are connected to the IP network through FXS ports. The integrated Music on Hold feature covers media server, data base administration, call control, media resource manager, and media control functional areas. The music on hold server provides the music resources/streams. These resources register with the Call Manager during the initialization/recovery period. Database administration provides a user interface to allow the Call Manager administrator to configure the Music on Hold feature for the device. Database administration also provides Call Manager call control with configuration information. Call control controls the music on hold scenario logic. The media resource manager processes the registration request from the music on hold server and allocates/reallocates the music on hold resources under the request of call control. Media control controls the establishment of media stream connections, which can be one-way or two-way connections. You must ensure that an end device is provisioned with music on hold-related information before music on hold functions for that device. Initializing a Call Manager creates a media resource manager. The music on hold server registers to the media resource manager with its music on hold resources. When an end device or feature places a call on hold, Call Manager connects the held device to a music resource. When the held device is retrieved, it disconnects from the music on hold resource and resumes normal activity. For music on hold to function, you must perform the actions in the following list: Configure music on hold servers and Configure audio sources. Always define audio sources first and then set up the music on hold servers, especially when multicast will be used. The user interface allows either step to take place first. And if an audio source is configured for multicast, the MOH server always transmits the audio stream, regardless of whether devices are held. Configure media resource groups. If multicast is desired, check the Use Multicast for MOH Audio check box. Do configure media resource group lists and assign media resource group lists and audio sources to device pools. Do Assign media resource group lists and audio sources to devices to override assignments made to device pools and always assign audio sources to lines to override device settings.