Mobile callers may hear you before they answer

People making mobile phone calls may sometimes be heard by the person they are calling several seconds before the ringtone stops, ORF reported. The caller may believe the other person has not yet answered, while the recipient can already hear everything being said.

The technical issue occurs because the conversation and the ringtone are transmitted through separate channels. Gernot Kubin of the Institute of Signal and Speech Processing at Graz University of Technology said the channels can become unsynchronised, causing one system component to switch earlier and activate the microphone.

The problem can affect all mobile networks, and similar reports can be found in internet forums. In some cases, the other person may hear up to three seconds of conversation while the ringtone is still playing.

Kubin recommends saying nothing until the other person answers to avoid embarrassing situations. This is particularly relevant when calling call centres, which can actively activate the microphone earlier.