Product Overview

The Cisco^® Packet Voice Digital Signal Processor Modules (PVDMs) enable Cisco 4000 Series Integrated Services Routers (ISRs) to provide rich-media capabilities such as high-density voice connectivity, conferencing, transcoding, media optimization, transrating, and secure voice for Cisco Unified Communications solutions. These new modules support unprecedented scale while allowing for a smaller solution footprint than ever before.

Features and Benefits

The PVDMs support digital voice connections, conferencing, universal transcoding, and media optimization services:

●   T1/E1 voice: One of the primary uses of PVDMs is to packetize digital voice into IP packets to enable time-division multiplexing (TDM) digital voice applications.

●   Conferencing: PVDM modules support ad hoc and meet-me conferencing with various codecs in conjunction with Cisco Unified Communications Manager and Cisco Unified Communications Manager Express.

●   Universal transcoding: In conjunction with Cisco IOS^® Software, the PVDMs support universal transcoding, which allows conversion from any supported codec to any other supported codec.

●   Transrating: The PVDMs support transrating, in which the same codec is repacketized in order to connect dissimilar networks that have different codec packetization periods.

●   Voice-quality management: The PVDMs perform compression, voice-activity detection, jitter management, and echo cancellation. The echo cancellation offered in the PVDMs has a tail length of 128 milliseconds and complies with ITU-T G.168.

●   Energy savings: The motherboard PVDMs (PVDM4s) offer multiple power-saving modes, including a power-saver mode when the module is not in use. In power-saver mode, each PVDM4 can save up to 5 watts of power.

The analog voice modules (FXS, FXO, and E/M) and Basic Rate Interface (BRI) digital voice modules for the 4000 Series ISRs contain built-in, nonconfigurable digital signal processors (DSPs) and do not require any additional PVDMs for voice packetization.

Refer to the PVDM Q&A for commonly asked questions.

Form Factor and Options

Cisco 4000 Series PVDMs are available in two form factors with four supported densities in each form factor:

●   Motherboard PVDMs (PVDM4) for densities up to 256 channels (Figure 1)

●   PVDM enhanced services modules (SM-X-PVDM) for densities up to 3080 channels (Figure 2)

The motherboard PVDMs are supported on all Cisco 4000 Series ISRs. They can be plugged directly into the single slot on the router motherboard or into the network interface module (NIM) that supports T1/E1 ports. A PVDM4 module plugged into the motherboard delivers IP-based voice services such as conferencing, media optimization, and transcoding only.

A PVDM4 module plugged into the T1/E1 NIM would be used for voice T1/E1 connectivity. Any excess channels can be reused toward other IP-based services supported on the motherboard slot. Enhanced DSP architecture accommodates a new packet-processing engine optimized for rich-media voice applications, while concurrently supporting the TDM-IP voice framework.

The PVDM enhanced services modules are supported on ISRs that contain an SM-X slot - namely the Cisco 4331, 4351, and 4451 ISRs. The SM-X modules support only IP-based voice services and cannot be used for TDM applications.