Dropped calls are often caused by weak internet connections, poor mobile networks, incorrect VoIP configuration, old hardware, or occupied bandwidth. The solution is to check the network, increase bandwidth, configure the correct codec, use standard equipment, and have a backup connection. Zenify recorded an uptime of 99.99% for its cloud platform.
TL;DR
- Dropped calls are often due to weak networks, incorrect VoIP configuration, and old equipment.
- Test internet: speed, latency, jitter, ping.
- Prioritize voice bandwidth, limit heavy loads at the same time.
- Correct codec, standard equipment, updated software.
- There is a backup transmission line/equipment in case of failure.
Why was the call dropped?
Cause | Explanation
Weak/unstable Internet | Poor Wi-Fi, low bandwidth
High latency/jitter | Slow network → error sound → drop
Bandwidth occupied | Video downloading/data sync
Wrong VoIP configuration | Codec, NAT, firewall blocking
Old/poor equipment | Headset, IP phone malfunction
Weak mobile network | Poor coverage, cell switching
How to diagnose
1. Check internet speed
Upload speed is especially important for calls.
Run the test multiple times a day, peak hours are often slower.
2. Measure latency and jitter
Ping >100ms, high jitter → call error, dropped.
Use specialized VoIP testing tools to measure voice quality.
3. Xem log cuộc gọi
Does the failure focus on any employee, any hour, or any area?
The entire system fails → common transmission problem; an employee → personal device/network issue.
8 ways to fix it
1. Prioritize voice bandwidth
Configure QoS to prioritize voice traffic in the router.
The call is not "interrupted midway" because someone is downloading a file.
2. Upgrade internet
Minimum bandwidth for a call: ~100kbps in each direction; More employees multiply.
Business Internet is more stable than home Internet.
3. Use a wired network for the agent
Wi-Fi is prone to interference and loss of signal. Important personnel use network cables.
If Wi-Fi is required: standard router, nearby, 5GHz band.
4. Correct codec configuration
Choose a codec that balances quality and bandwidth (G.711 when the network is good, G.729 when the network is weak).
Wrong codec causes sound to break, freeze, or drop.
5. Update device and software
Headsets, IP phones, softphone apps updated to new versions.
Old and outdated equipment is a source of silent failures.
6. Configure firewall/NAT correctly
Open necessary ports for VoIP, configure NAT so calls go through properly.
Firewall blocking the port is the culprit "can make calls, but can't hear".
7. Transmission redundancy
There is secondary internet (4G/5G) that switches over when the main internet fails.
Network incidents are unavoidable, backup helps the switchboard not to die.
8. Monitor uptime and quality
Report drop rate and sound quality by day.
Deteriorating trend → early detection before customers complain.