The issue is if an additional three Packet Voice/Data Modules-12s (PVDM-12s) can be added to the High Density Voice Network Module-1T1-24 (NM-HDV-1T1-24) on a Cisco 2650 router with two PVDM-12s. Other issues consist of whether this module can be used strictly for conference calling, what the restrictions are on how the PVDMs are divided up, if there are enough PVDMs for the Public Switched Telephone Network (PSTN) gateway access and (assuming all are G.711 calls) how many PVDMs are left for conferencing.
The NM-HDV Farm module ships with two SIMMs and is able to handle three additional SIMMs. Each SIMM contains three Digital Signal Processors (DSPs). Each DSP supports four transcoding sessions (or one conference bridge). When you create the PRI group, the DSPs needed to service all of the channels are automatically allocated, which consist of two PVDMs (six DSPs).