A fault in Australian telecom company Optus's land and mobile networks has engineers baffled.

The glitch allows customers to eavesdrop on others' phone calls.

It was originally thought to be limited to the Optus pre-paid mobile service, but smh.com.au readers have subsequently described the issue occurring in Optus' landline network as well.

According to the online broadband community, Whirlpool the glitch works like this.  If a customer is out of credit they can ring customer care. A recorded message tells me that I have insufficient credit left to make the phone call, but instead of hanging up it begins to ring and it is possible to hear conversations of other mobile phone users.

It seems that the call logs into the next phone call going through the tower or exchange."
The Optus landline service has a similar problem.  If a customer responds to the tone on the handset notifying that they have voicemessages stored, by pushing the voicemail button on my landline handset they will connect to other customers trying to get their voicemail.

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