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The Cisco 3825 Integrated Services Router does not detect the voice cards already installed


Core Issue

If there are no Digital Signal Processors (DSPs) available on the router, then the router fails to detect the voice cards installed. You can verify this with the show diag or show version commands on the router. These commands provide information about the packet voice/data modules (PVDMs) that are installed.


PVDMs are optional components of these router platforms, with the exception of voice bundles that have one PVDM included. Cisco 3800 Series routers have four PVDM slots each. You can calculate PVDM reqiurements with the DSP Calculator tool.

The DSP Calculator tool tells you how many and what kind of PVDMs you need for your hardware and codec usage.  In order to resolve the issue, install the PVDMs accordingly.

For more information about PVDMs, refer to IP Communications Voice/Fax Network Module

Problem Type

Gateway or module

Common Software and Product Issues

Installation problems

Failure Type

Bad operational behavior

Nothing detected: Not detected, recorded, understood, recognized, etc.

Voice Gateway Hardware Components

Voice modules

Voice Gateways

3800 Series Integrated Services Routers

IOS gateways

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