The PVDM-12= is a 12-channel packet voice DSP module upgrade spare. Packet Voice Digital Signal Processor Module (PVDM-12=) provides the ability to increase the voice processing capabilities within a single network module.This product must be used in combination with the NM-HDV= to build NM-HDV-1J1 products. This product can also be used to upgrade the NM-HDV-1J1-30 products to the Enhanced version.