Resolving PRI DSP Resource Errors on Cisco ISR 4300

350-801 By islever Editorial Last updated Aug 20, 2026

Short answer

D Install the PVDM directly to the NIM card.

Question

An engineer is configuring a PRI card on a Cisco ISR 4300 Series Router. When the engineer configures the voice PRI on the router, this error is received: "T1 0/1/0: No DSP resources to configure voice feature". Which action must the engineer take to resolve the issue if a PVDM card was installed in the motherboard?

Install the NIM card on a different slot.
Replace the memory slot in the motherboard.
Replace the flashcard, restart the router, and try it again.
Install the PVDM directly to the NIM card. Correct Answer

Key Takeaways

The exam tests knowledge of physical slot constraints and DSP assignment rules; the common trap is assuming motherboard resources are globally available to all interface modules.

This question addresses the hardware architecture of Cisco ISR 4000 Series routers regarding DSP resource allocation. The community consensus is that onboard PVDMs are reserved for IP services and cannot be shared with TDM NIM cards, requiring a dedicated NIM-PVDM.

Common mistake: Candidates often choose Option A (moving the card), mistakenly believing the issue is a slot conflict or compatibility error rather than a specific DSP resource availability constraint defined by the platform's hardware design.

Expert Analysis

Why the Answer Is Correct

On the Cisco ISR 4000 series, the motherboard PVDM slots are specifically designated for IP media processing tasks such as transcoding and conferencing. They are architecturally isolated from the Network Interface Module (NIM) slots used for traditional TDM interfaces like PRI. Therefore, when a T1/E1 NIM requires DSP resources for voice feature configuration, it must utilize a dedicated PVDM module installed directly into the NIM itself (NIM-PVDM).

Why the Other Options Are Wrong

Option A is incorrect because moving the NIM to a different slot does not change the fact that the NIM cannot access motherboard PVDMs regardless of the slot position. Option B is irrelevant as there is no 'memory slot' replacement procedure for this type of resource error. Option C is incorrect because replacing flash does not allocate additional DSP hardware resources needed for the voice feature.

Community Comment Notes

Comment [1] provides critical technical context, stating that while PVDM4 chips can be on the motherboard for IP services, they are not accessible to NIMs. Comment [2] reinforces this by noting that on-board PVDMs are for conferencing/transcoding only. Comment [3] offers a useful link to Cisco documentation explaining the NIM-PVDM concept, which validates the need for installing the DSP module on the NIM card.

Exam Strategy

Always distinguish between IP-based DSP usage (motherboard) and TDM-based DSP usage (NIM/PIM) in ISR 4000 questions. If an error involves a legacy interface (PRI/BRI) lacking resources, look for solutions involving adding DSPs to the interface module itself.

Community Votes

83%

17%

83% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 4 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 4

itGoat 👍 3 Answered D

There is only one PVDM slot on the motherboard. The Time Division Multiplexing (TDM) cards cannot use the motherboard PVDMs. Dependent upon the number of channels required, the appropriate DSP module is installed on the NIM. For IP services such as to transcode and conference, the PVDM4 DSP module can be installed on the motherboard of the ISR 4000 Series platform. If the show inventory output shows this information, it signifies that the PVDM card is installed on the motherboard. https://www.cisco.com/c/en/us/support/docs/routers/4000-series-integrated-services-routers/118792-config-isr-00.html I think D
cb586d3 👍 2 Answered D

"The on-board PVDMs can be used for conferencing/transcoding but aren't accessible to the NIMs." Seems to be D.
Zatingke 👍 1 Answered A

https://community.cisco.com/t5/collaboration-blogs/introducing-nim-pvdm-dsp-voice-module/ba-p/4176223 NIM-PVDM is the Next-generation digital signal processor (DSP) module with an onboard DSP daughter card which eliminates the need to procure an additional T1/E1 NIM card in order to utilize a PVDM4 chip for IP media services.
b3532e4 👍 1

I think D

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