Why Can Only One Person Hear the Other on an Office Phone Call?

A customer can hear reception, but reception hears silence. The fact that the call rang and connected tells you that call signalling worked far enough to establish a call. Voice has its own path in each direction, and one path can fail while the other still works.

Record the direction and the call path

Use an approved test number and record who can hear whom, the time, the extension, and whether the problem appears on inbound or outbound calls. Try a second handset on the same network and a call between two internal extensions. If the issue starts only after a transfer or only affects a remote branch, record that too. A muted headset and a provider-side media issue can sound similar to the person receiving the call.

Separate the handset from the media path

Swap the handset or headset with a known-good unit and repeat the same call. If internal calls work and several handsets fail only on external calls, have the phone-system administrator review the trunk and any network boundary the media crosses. Cisco’s IP telephony troubleshooting reference describes checking connectivity and following the Real-time Transport Protocol (RTP) stream from its source when isolating one-way audio.

Give your phone provider and network administrator the same call reference and time so they can compare evidence on each side. Ask where the missing direction stops and whether a recent network, trunk or phone-system change affected the path. Use approved diagnostic access and minimise what you retain from call traces. Broad firewall changes can create new problems and make it harder to identify the original cause.

Repeat the cases staff rely on

After an approved change, repeat inbound and outbound calls, hold and resume, and the relevant transfer or branch path. Confirm that both parties hear each other and record what changed. If the issue is which extension receives a call rather than what either party hears, use the office phone routing guide.

ITZ’s IP telephony and business phone systems service can help scope a handset, trunk and network review. Share the affected extension and which direction loses audio.

Review your one-way call audio

Bring the phone-system model, a timestamped test case and the results of your internal and external call comparison. Use the form to discuss where to investigate next. Review Your One-Way Call Audio