How to Troubleshoot Deskphone Audio Quality on KrispCall

If you're experiencing audio issues on your desk phone, such as choppy voice, echo, static, or one-way audio, it could be due to a number of reasons ranging from network conditions to hardware faults. 


Listed below are the most frequent causes and steps to resolve common audio quality issues with desk phones connected to KrispCall.


Initial Checks

Before diving into specific fixes, run through these quick checks first:

  • Restart your desk phone and router: Restarting both devices can clear temporary network or device glitches.
  • Check KrispCall’s service status: Visit the KrispCall official page to confirm there are no ongoing outages or network disruptions.
  • Verify your desk phone is linked: Make sure your desk phone is properly connected to your KrispCall account using the SIP credentials.
  • Inspect cables: Check all Ethernet and handset cables for visible damage or loose connections. Replace any suspect cables.


Perform a Speed Test

A slow or unstable internet connection is one of the most common causes of desk phone audio issues. This helps confirm whether your network is the root cause and provides data to share with your ISP or IT team if needed.


To do this:

  • Go to speedtest.net on a device connected to the same network as your desk phone.
  • Run three to four consecutive speed tests to ensure consistent results.
  • Check the following against the minimum requirements for clear VoIP calls:
    • Download and upload speed: At least 100 kbps per active call. If multiple phones are in use simultaneously, multiply this by the number of concurrent calls.
    • Ping (latency): Should be under 60ms. Values between 5–48ms are considered normal.
    • Upload speed consistency: Should not fluctuate more than 20% between tests.


If your results fall below these thresholds or fluctuate significantly between tests, contact your internet service provider or IT team before proceeding with the steps below.


Troubleshoot by Issues


Identify your specific audio issue below and follow the recommended steps:


Choppy, Robotic, or Garbled Audio

Cause: Network congestion, packet loss, or jitter (inconsistent delivery of audio data packets)

To fix this: 

  • Pause any bandwidth-intensive activity, such as video streaming, large file downloads, or cloud backups, during calls.
  • Connect your desk phone directly to the router using an Ethernet cable, bypassing any network switches, to rule out switch-related congestion.
  • Enable QoS (Quality of Service) on your router** **to prioritize voice/VoIP traffic. Look for this in your router's Advanced or Traffic Management settings.
  • Adjust the jitter buffer to 30–50ms. A buffer that is too small discards packets, and one that is too large introduces noticeable delay.
  • Update desk phone firmware, as outdated firmware can cause audio glitches.


Echo or Audio Feedback

Cause: High latency, speakerphone use, or high microphone gain 

To fix this:

  • Switch from speakerphone to the handset or a headset, as the speakerphone can pick up audio output and feed it back into the call.
  • If the phone is in an enclosed space with the volume set to moderate or high, move it out of the enclosed area or lower the volume.
  • Lower the TX (transmit) gain in your desk phone's Audio Settings to prevent the microphone from picking up excess sound.
  • Enable echo cancellation. Look for this option under Audio Settings in your desk phone's menu or admin web interface
  • Run a ping test to check network latency, as echo becomes noticeable when latency exceeds 150ms.
  • Update your desk phone firmware, as audio processing bugs in older versions are a known cause of persistent echo that doesn't respond to device-level fixes.


One-Way Audio

Cause: NAT (Network Address Translation) or firewall issue blocking RTP media streams.

To fix this:

  • Disable SIP ALG (a router feature that often disrupts VoIP traffic) on your router.
  • Open the required RTP ports (10000-20000) on your firewall to allow KrispCall media traffic.
  • Temporarily disable the firewall to test the connection.


Low or No Audio Volume

Cause: Device settings or hardware issue

To fix this: 

  • Increase the speaker and ringer volume during an active call.
  • Adjust the RX (receive) gain in your desk phone's Audio Settings to boost the volume of incoming audio at the device level.
  • Switch between the handset and speakerphone to identify whether the volume issue is limited to one audio output or affects the device overall.
  • If you're using a headset, confirm it is firmly plugged into the correct port. 


Static, Crackling, or Background Noise

Cause: Electrical interference or faulty hardware

To fix this: 

  • Replace any frayed or damaged Ethernet or handset cables.
  • Confirm you are using the correct power adapter for your desk phone model or a compatible PoE (Power over Ethernet) switch.
  • Position all cables away from sources of electromagnetic interference, such as power supplies, monitors, and fluorescent light fixtures.
  • Disconnect any inline accessories, such as line splitters, third-party caller ID units, or other devices connected between the phone and the network.
  • Swap the handset with a different one to determine if the noise is coming from the handset hardware itself. If the static disappears, the original handset needs to be replaced.


Not sure what’s causing the issue? Use the following to narrow it down:

  • The problem occurs only with one specific contact; the issue is likely on their end.
  • The problem happens at the same time every day; your network may be experiencing peak-hour congestion.
  • The problem affects only one desk phone; it's a hardware-specific issue. Test with a different device.


Note: If you've gone through all the steps above and the issue persists, please reach out to the KrispCall Support Team. Our team will help identify whether the problem is related to your device, network, or account configuration.


When you reach out, please include the following details so our team can assist you faster:

  • Desk phone model and firmware version
  • Network type (Wi-Fi or wired)
  • Time and frequency of the issue
  • Sample call details (timestamps or contact numbers affected)

Updated on: 12/05/2026

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