Troubleshooting: how to solve the most common problems with IP-telephony

Publication date: 9.06.2022

IP-telephony is one of the most stable ways of communication for business; it literally revolutionized the communications technology market. This is a flexible solution that can be implemented in small and large businesses. But like any other technical solution, IP telephony can have its own problems that need to be fixed.

The good news is that most of them are fairly easy to fix without drastic steps. However, now you will see for yourself.

This article is about the most common problems with IP telephony and how to solve them.

Get to work!

The most common causes of problems

Most often, IP-telephony is “buggy” for very prosaic reasons:

  • unstable Internet connection → solved by improving the quality and speed of communication (changing the package with your provider or connecting to another provider);
  • insufficient network bandwidth (the network does not have enough resource to process) → solved by increasing the bandwidth;
  • packet loss (data loss during transmission) → most often a natural process, which, however, can be minimized after identifying the exact cause (hardware/software).

Bandwidths, packet loss… Let’s look at the more practical side of the matter: what specific problems you may notice in your connection – and how to solve them.

Interrupted voice

This is the same situation when “I … ne yo … to te … abo …”: the caller’s voice is interrupted by short pauses.

The most common cause: problems with network equipment, when the router can’t handle the load and the number of connected devices. If the problem occurs from time to time, and not constantly, it is likely that this load is caused by the operation of some site or service that also uses a lot of bandwidth, for example, like streaming services.


  1. Test communication on another computer on the same network, and shut down other computers on the same network and evaluate the changes.
  2. Find and disable (if possible) applications for streaming files, for example, streaming services, YouTube, Spotify, Netflix.
  3. Check the configurations of the QoS router– it should have a priority set fortelephony traffic.
  4. Scan PC for malware. They can load the computer with complex processes that are not visible to the user, but “eat up” a lot of resources. An antivirus program and regular scans are an absolute must-have.
  5. Assess the compliance with the declared bandwidth. The Internet provider’s tariff always indicates the bandwidth. Check the actual characteristic in services (for example, in or and if it is lower than stated, contact the provider to find out the reasons.

Audio delay or echo

Perhaps the most common problem – and, what luck – is almost the easiest to solve.


  1. Check the acoustics of the headphones. Often an echo comes from a headphone that is too loud: the sound from it is picked up and amplified by the microphone, creating the same echo. You can check by closing the microphone (if the problem was in it, the echo will disappear). To resolve the issue, turn down the headphone volume or move the microphone further away from the speaker.
  2. Eliminate electromagnetic interference from other equipment. If the equipment for IP-telephony is located close to other equipment, electromagnetic interference may occur. It is better when the phone, PC, router and voice gateway are at some distance from each other.
  3. Remove some equipment. If you use splitters or caller ID devices, they can also create electromagnetic interference and, as a result, cause echoes. Try turning them off and see how the sound quality changes.
  4. Check ISP ping. Echo can occur not only due to hardware problems, but also due to network problems that affect signal quality. For example, when ping is above 50 milliseconds (ms). To check your ping time, test your network speed with services like or
  5. Update hardware. Old equipment can create electrical vibrations that cause echoes. Eliminate all previous factors to be sure that the cause of the echo is in the equipment. Check the connection on other devices: handset (if you used a headset), wired phone (if you had a wireless one), etc. Also try connecting the equipment through other cables – damage to them can also cause communication interference.

Sound crackles or jitters during a call

Crackling sound can occur for the same reasons as echo or audio delay: insufficient network bandwidth, electromagnetic interference, physical damage to equipment.


Troubleshooting: how to solve the most common problems with IP-telephony


  1. Check the QoS router configuration: IP telephony should have priority.
  2. Test network bandwidth; if it is lower, contact your ISP for clarification.
  3. Inspect all cables. If the cable is wet or damaged, this can not only affect the quality of communication, but also create quite risky situations in terms of security.
  4. Rearrange equipment: check that different devices do not create electromagnetic interference that disrupts operation.

Voice compression (codec)

Compression of audio data is needed to reduce the amount of data. Less data → faster transfer → less resource cost → less risk that the call will be interrupted due to communication problems. If something goes wrong with the codec, it directly affects the quality of the calls.


  1. Check codec. If the codec is incorrect, compression or transmission problems may occur. Try changing the codec to another one to see if this is the problem.
  2. Estimate throughput. If problems occur during office peak hours (when most calls come in), it’s probably a matter of bandwidth again. Here everything is okey with the codec itself, but the amount of data to be transferred exceeds the capacity of the system. To fix this, you may need to upgrade your Internet package – or change your provider.

Unstable connection

Unstable communication is expressed in a large variation in quality from call to call. We call once – and everything is perfect, we call twice – and it is impossible to speak.

The most common reason: telephony not optimized for peak loads. That is, the system itself is built correctly, but during the growing load on the network, it starts to fail.


  1. Remove applications that use high network bandwidth: Netflix, Spotify, YouTube.
  2. Assess the bandwidth and, if it is not enough regularly, upgrade the Internet package or change the provider.
  3. Check the QoS router: IP telephony data must have priority.

Call breaks

The most common cause is an overloaded office network or faulty hardware.


  1. Assess the bandwidth and, if it is not enough regularly, upgrade the Internet package or change the provider.
  2. Check the QoS router: IP telephony data should have priority in it.
  3. Check the connection on other equipment: perhaps a hardware problem and to solve it, you need to update the equipment.


In total, we considered the 6 most common problems:

  1. Intermittent voice.
  2. Audio delay or echo.
  3. Crackling or rattling sound.
  4. Voice compression.
  5. Unstable connection.
  6. Call breaks.

Most often, these issues are resolved by such measures:

  1. Setting the priority in the QoS router.
  2. Increasing network bandwidth.
  3. Disable streaming services.
  4. Rearranging equipment to avoid interference.
  5. Check cables for damage.

If you are not sure what the problem is, contact your network administrator or contact UniTalk IP telephony technical support!