Why Can One Person Hear the Call but the Other Side Cannot?

One-way audio in a voice call often points to a media path, firewall, NAT, headset, or network issue rather than call signaling. It can affect only certain locations or call directions.

What to check

Compare internal and external calls, test another handset and network, inspect the phone’s registration and media path, and review firewall or SIP ALG changes. Record timestamps and call direction for affected examples.

Recommended next step

Change one network or endpoint variable at a time and retest both directions. Informatix Systems can assess business VoIP connectivity and coordinate a structured fault isolation.