Poor call quality can include crackling audio, robotic speech, delay, echo, dropped audio, or calls where one person cannot hear the other.
One-way audio is where one side of the call can hear the other person, but the other side cannot hear them back.
Common causes
Poor VoIP call quality can be caused by:
- Internet connection issues
- Packet loss
- High latency
- Jitter
- Wi-Fi issues
- Firewall or router configuration
- SIP ALG
- Local network congestion
- Faulty cabling
- Poor handset connectivity
- Bandwidth limitations
VoIP relies on a stable internet connection. Even if web browsing appears to work, small amounts of packet loss, latency, or jitter can affect call quality.
Check whether the issue affects one user or everyone
Please check whether the issue affects:
- One handset
- Multiple handsets
- Inbound calls only
- Outbound calls only
- Internal calls
- External calls
- Calls at certain times of day
If only one user is affected, the issue may be local to that handset, cable, switch port, or device.
If all users are affected, the issue may be related to the internet connection, firewall, or wider network.
Avoid testing over Wi-Fi
Where possible, VoIP desk phones should be connected by Ethernet rather than Wi-Fi.
Wi-Fi can be affected by signal strength, interference, distance, building layout, and the number of connected devices. If call quality issues only affect Wi-Fi-connected devices or softphones, the wireless network should be checked.
When to contact Fastnet
If poor call quality continues, please contact the Fastnet Helpdesk.
When contacting us, please provide:
- Your company name
- The affected extension or phone number
- Whether the issue affects one user or multiple users
- Whether the issue affects inbound, outbound, or both
- Example call times
- The caller number and called number for example calls
- Whether the issue is constant or intermittent
- Whether the internet connection is otherwise working
- Whether the phone is connected by Ethernet or Wi-Fi
- Any recent changes to your internet, firewall, or network
Example call details are especially useful, as they allow us to investigate specific calls rather than looking at the service generally.