This article walks through the most common causes and resolutions when a Yealink desk phone rings, the call is answered, but no audio is heard by one or both parties.


Common Symptoms

  • Phone rings normally

  • Call connects successfully

  • No audio when the caller or callee answers

  • Issue may affect:

    • Both inbound and outbound calls

    • Only one direction (one-way audio)


Step-by-Step Troubleshooting

1. Confirm the Audio Path (Rule Out Hardware)

Start with the basics to eliminate physical causes:

  • Test handset, speaker, and headset modes

  • Disconnect any wired or Bluetooth headset

  • Increase volume during the active call

  • Try a different handset cord if available

✅ If audio works on one mode but not another, the issue is likely hardware-related.

2. Power Cycle the Phone and Network Equipment

Temporary network states can block audio streams.

  1. Power off the Yealink phone

  2. Reboot the router and firewall

  3. Wait 2–3 minutes

  4. Power the phone back on and retest

3. Check Network & Firewall Rules (Most Common Cause)

Yealink phones rely on RTP (audio) ports to pass voice traffic.

Ensure the firewall allows:


❗ If SIP signaling works but RTP is blocked, calls will connect with no audio.

Also check:

  • SIP ALG is disabled

  • No symmetric NAT restrictions

  • No packet inspection blocking VoIP

4. Update Phone Firmware

Outdated firmware can cause:

  • Audio bugs

  • Codec negotiation issues

  • Network instability

Actions:

  • Check the current firmware version

  • Update to the recommended stable release

  • Reboot and retest

5. Test From an Alternate Network

To isolate the issue:

  • Move the phone to:

    • A different office

    • A hotspot

    • A known-good network

✅ If audio works elsewhere, the issue is local network-related.

When to Escalate

on-siteEscalate to SoundCurve Support or your onsite IT team if:

  • Multiple phones experience the same issue

  • Audio fails only on certain call routes

  • Firewall changes are restricted

Provide:

  • Phone model & firmware

  • Local IPv4 to SoundCurve support by visiting: ip4.me 

  • Time of failed test calls

  • Call direction (inbound/outbound)

  • Confirmation SIP ALG is disabled within the router settings

Summary

First, confirm that the handset is properly connected to the Yealink desk phone. Ensure the Headset mode is not accidentally enabled, Do Not Disturb (DND) is turned off, and that the phone successfully receives audio when Speaker mode is enabled.