REFURBISHED
Cisco
Cisco PVDM4-256 Refurbished 256-Channel DSP Module
MPN: PVDM4-256
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Lifetime
Warranty
ISO 9001
Certified Testing
R2v3
Responsible Refurb
25+
Years
5K+
Customers
ISO
Certified
✓
Tested
Every WhaleyComm unit is professionally tested, reset to factory defaults, and certified by our in-house engineers — the same standard trusted by 5,000+ organisations across 25 years. Not a refurb marketplace. A certified lifecycle partner.
256 channels of DSP power, professionally tested, backed by a Lifetime Warranty.
This refurbished Cisco PVDM4-256 is a fourth-generation, 256-channel Digital Signal Processor module, professionally tested and reset to factory defaults before shipment. Delivering up to 256 channels of G.711 voice processing or 128 channels of G.729, it is purpose-built for high-density Unified Communications deployments across Cisco ISR 4000 Series and Catalyst 8000 Edge platforms. Every unit is inspected to the same standard as new — you receive enterprise-grade DSP performance at a significantly reduced cost.The PVDM4-256 is engineered around Cisco's fourth-generation DSP architecture, optimized for the full range of rich-media voice workloads: TDM-to-IP conversion, universal transcoding across codecs including G.711, G.729, and iLBC, high-density conferencing, and encrypted voice streams for secure Unified Communications environments. Its compact, low-power design makes it equally at home in a dense branch router rack or a large enterprise edge deployment.
WhaleyComm has served 5,000+ enterprise customers across 25+ years of IT hardware refurbishment. Sourcing the Cisco PVDM4-256 through WhaleyComm means verified performance, full certification chain, and a Lifetime Warranty — without paying new list price.
Technical Specifications
Manufacturer
Cisco
Model
PVDM4-256
Product Type
DSP Module
Generation
Fourth-generation
Maximum Voice Channels (G.711)
256
Maximum Voice Channels (G.729)
128
Supported Codecs
G.711, G.729, iLBC
Supported Voice Types
T1/E1 digital voice (PRI, CAS, channelized)
Capabilities
Voice processing, conferencing, transcoding, media termination, secure voice
Condition
Refurbished
Ideal Use Cases
High-Density Branch Voice Deployments
The PVDM4-256 supports up to 256 simultaneous G.711 channels, making it well-suited for branch offices or enterprise sites requiring large-scale concurrent voice sessions without multiple DSP modules.
TDM-to-IP Voice Migration
Enterprises transitioning from legacy TDM infrastructure to IP telephony can use the PVDM4-256 to handle T1/E1 PRI and CAS interfaces, bridging existing circuits to modern VoIP platforms during or after migration.
Conferencing and Media Termination
The module provides dedicated DSP resources for on-router conferencing and media termination point services, reducing load on the router CPU and maintaining call quality at scale.
Universal Transcoding Between Codecs
Environments running mixed codec deployments — such as G.711 endpoints alongside G.729 or iLBC devices — can use the PVDM4-256 for real-time transcoding to ensure interoperability and voice quality.
Secure Unified Communications
The PVDM4-256 supports encrypted voice streams within Cisco Unified Communications environments, enabling organizations with compliance or confidentiality requirements to process secure voice at high channel density.
Cisco SRST and CME Deployments
For sites running Cisco Survivable Remote Site Telephony or Cisco Call Manager Express, the PVDM4-256 provides the DSP resources needed to sustain local call processing during WAN outages or as a standalone telephony solution.
What's Included
Cisco PVDM4-256 DSP module
Lifetime Warranty — No Time Limits. No Questions.
Every WhaleyComm unit ships with a Lifetime Warranty. If it fails under normal operating conditions at any point, we replace it. We have stood behind our hardware for 25 years and 5,000+ customers — that is not a marketing line, it is our operating standard.
Compatibility Details
Review supported optics, cables, software, management protocols, and environment-specific compatibility guidance.
Cisco ISR 4000 Series
ISR 4321
ISR 4331
ISR 4351
ISR 4431
ISR 4451-X
Cisco Catalyst 8000 Edge Platforms
For compatibility verification specific to your IOS-XE version or deployment environment, contact our engineering team: +1 214 607-4800 or sales@whaleycomm.com
For compatibility verification specific to your environment, contact our engineering team: +1 214 607-4800 or sales@whaleycomm.com
Shipping & Returns
Clear fulfilment, tracking, return, warranty, and support information for enterprise hardware orders.
Shipping
Orders typically ship within 1-2 business days after payment confirmation. Tracking details are shared once the order has been dispatched.
Returns
Eligible products can be returned according to WhaleyComm's return policy. For DOA, warranty, or product-related issues, contact the support team for replacement or resolution.
Frequently Asked Questions
Product-specific answers about compatibility, testing, warranty, fulfilment, and purchase confidence.
The PVDM4-256 supports up to 256 channels when using the G.711 codec, which requires more DSP resources per channel due to uncompressed audio. When using G.729, a compressed codec that demands greater processing per channel, capacity is 128 simultaneous channels. Your actual channel count will depend on the codec mix in your environment.
The PVDM4-256 is supported on the Cisco ISR 4000 Series (ISR 4321, 4331, 4351, 4431, and 4451-X) and on Cisco Catalyst 8000 Edge platforms. If you need to confirm compatibility with a specific platform or IOS-XE version in your environment, contact our engineering team at +1 214 607-4800 or sales@whaleycomm.com.
Yes. The module supports secure voice stream processing within Cisco Unified Communications environments, enabling encrypted voice at high channel density without offloading that work to the router CPU.
Yes. Every WhaleyComm unit ships with a Lifetime Warranty. If it fails under normal operating conditions at any point, we replace it at no cost — no time limits, no questions asked.
Every unit goes through our ISO 9001-certified testing process: full power-on diagnostics, port-by-port functionality testing, firmware verification, factory reset, and final inspection. A Certificate of Testing ships with every unit.
Cisco PVDM4-256 Refurbished 256-Channel DSP Module
$125.00
Cisco
Cisco PVDM4-256 Refurbished 256-Channel DSP Module
MPN: PVDM4-256
$125.00
In Stock — Ships Same Day
