Q. Can the PVDM2 and PVDM3 DSP modules coexist on the Cisco 2900 and 3900 Series routers? A. Yes, they can coexist as long as they are not both installed in the same domain. The motherboard PVDM slots form one domain and each service-module slot forms a separate domain. The motherboard domain can contain either all PVDM2 modules or all PVDM3 modules. A service-module domain can contain only PVDM2 modules housed by the NM-HDV2 carrier card. If a mix of PVDM2s and PVDM3s is detected on the motherboard, the PVDM2s are deactivated, allowing only the PVDM3s to be active. If PVDM2s are detected in service-module slots and PVDM3s are installed on the motherboard, then both continue to function in their own domain and coexist.