Poor call quality

Symptom

During calls, the audio:

• cuts in and out, is choppy or drops words (the most common problem);
• sounds robotic, underwater or far away;
• has a delay, so you talk over each other;
• has static.

If the whole call disconnects, see Calls drop after a few seconds. If you only hear an echo, see Echo on calls.

Why it happens

Call audio is sent in thousands of small packets. Packets that are lost on the way are never resent, so you hear a gap. That’s what “cutting in and out” is. Packets that arrive late or unevenly (jitter) make audio sound robotic or delayed.

Most quality problems come from a congested or faulty internet connection somewhere between the phone and our servers, or between our servers and the other caller’s network.

Quick checks

1. Check for a known problem: Support › Network status.
2. Who’s affected? One user, everyone at one site, or every call to one carrier or person? This tells you where to look.
3. Is something using the internet heavily? Large downloads, backups, video streaming and video meetings on the same connection compete with calls.
4. Wi-Fi or cable? Try the same call on a wired connection.

Likely causes and fixes

1. Wi-Fi

Wi-Fi drops and delays packets, especially far from the access point or with many devices.

Fix: plug desk phones and computers into the network with a cable. For the Webphone mobile app, move closer to the access point or switch to mobile data.

2. Not enough bandwidth, or no priority for calls

When the connection is full, call packets wait in line or are dropped.

Fix:

• Check your internet plan’s upload speed. Upload is usually what runs out first.
• Turn on QoS (quality of service) on the router and give voice traffic priority.
• Schedule backups and large uploads outside business hours.

See Network requirements.

3. Router or network equipment

Fix: check cables and ports for damage, restart the router and switches, and update their firmware. Turn off SIP ALG on the router.

4. Packet loss on your internet connection

If problems continue on a wired connection, the internet connection itself may be losing packets.

Fix:

1. Test another connection. Connect the phone or computer to a mobile hotspot and make test calls. If quality improves, the problem is your internet service.
2. Gather evidence. Internet providers usually need proof before they’ll investigate. Run an MTR test (a traceroute repeated over time) to the SIP server in the device’s SIP credentials (PBX › Devices, the Domain). Use WinMTR or PingPlotter on Windows, or mtr on macOS or Linux. Let it run for a few hours during business hours and save the results.
3. Report the fault to your internet provider with the results. Loss that starts at one hop and continues to the end shows where the problem is.

Allow ping (ICMP) replies on your router’s internet (WAN) side so the support team can test your connection from our end.

5. The other caller’s network

If only certain callers are affected, for example people on one mobile network or in one area, the problem is likely on their side. Note the numbers and times and include them in a support ticket.

Find which part of the call is affected

Call recordings help work out where the audio is lost. Turn on automatic recording for the affected User, then listen to a bad call:

What the recording sounds like	What it suggests
Both sides clear, but the user heard gaps	Audio is lost on the way to the user’s phone (their download), or the problem comes and goes and the recording missed it.
The user’s voice has gaps	Audio is lost on the way from the user’s phone (their upload).
The other caller’s voice has gaps	The other caller’s connection or network.
Both sides have gaps	The problem may be wider. Check Network status and contact support.

Ask the user to listen as well: what they heard on the call may differ from the recording.

Note

For partners: if several of your customers report the same symptoms at the same time, compare them before escalating. A shared pattern suggests a wider network issue rather than a single site.

When to contact support

Create a support ticket with:

• dates and times of affected calls (with your time zone), and the numbers involved;
• what it sounded like and who heard it (the user, the other caller, or both);
• the device type and whether it’s on Wi-Fi or cable;
• your internet provider and connection type;
• MTR results and call recordings, if you have them.