/mcpdevices result in logging some alarm messages and automatically reducing the call count for the restricted media device. A media kernel driver with a capacity of 6000 streams might not support that many simultaneous media device connections. Note Interwork External Multicast MOH to Unicast MOH With this release, you can configure a Cisco Unified Survivable Remote Site Telephony (SRST) router as an audio source. This router provides multicast MOH audio for devices that are capable of multicast reception. In this approach, devices act as if Cisco Unified Communications Manager is sending the multicast MOH audio. However, devices that are capable of only the unicast reception cannot hear the MOH audio that an external MOH source (for example, Cisco Unified SRST router) sends. Examples of devices that are capable of unicast reception only can be public switched telephone network (PSTN) phones, destination to session border controllers (SBC), and Session Initiation Protocol (SIP) trunks. In this release of Cisco Unified Communications Manager, this feature is enhanced to receive multicast MOH audio from an external audio source and send it as unicast MOH audio. Cisco Unified Communications Manager uses this feature to play multicast MOH audio as unicast MOH for the devices that are capable of unicast MOH reception only. Examples of an external MOH audio source can be a Cisco Unified SRST router or software that can send multicast MOH audio. An administrator configures the fields for this feature from Cisco Unified CM Administration Music On Hold Audio Source Configuration window. • This feature has no impact on existing functionality of playing multicast MOH audio using an external audio source for the devices that are capable of multicast reception. • For the unicast media connection, Cisco Unified Communications Manager MOH Server plays the initial announcement and periodic announcement even if you configure the MOH audio source with external multicast source. Note Configuration Tips for the Codec-Specific Inbound Audio Stream Configure an external multicast audio source, such as Cisco Unified SRST router, to MOH server for streaming the required audio feed. To configure an external multicast audio source, such as a Cisco Unified SRST router, configure the Source IPv4 Multicast Address and Source Port Number fields in the MOH Audio Source Configuration window. • Cisco Unified Communications Manager listens to multicast G.711 mu-law stream on external multicast IP address and port that you configured on the MOH Audio Source configuration window. An MOH server can transcode between the G.711 mu-law or a-law or L16 256K wideband MOH codecs. The external multicast RTP stream uses G.711 mu-law codec for MOH as a source for G.711 mu-law or a-law or L16 256K wideband MOH codecs. For G.711 a-law and wideband calls, Cisco Unified Communications Manager MOH server transcodes the inbound G.711 mu-law stream to outbound G.711 a-law or wideband stream before sending it to the device. Feature Configuration Guide for Cisco Unified Communications Manager, Release 15 and SUs 619 Custom Features Interwork External Multicast MOH to Unicast MOH