Auckland's ZM radio station says it has not had direct complaints about newly introduced technology that switches FM car stereos by remote control to ZM traffic reports when a button is pushed in the broadcaster's studio.

But ZM operations manager Christian Boston said the station would stop triggering car radios to automatically switch to the traffic report if it upset significant numbers of listeners.

"It's not our intention to spam people or to hijack their radios or irritate anyone," he said. If there was too little understanding of the technology, the station would turn off its traffic feature, he said.

"But I haven't had one complaint."


The Radio Data Service (RDS) technology has been common in Europe for a decade, but has been used by ZM for only about six months.

In all, six Auckland FM stations, and one each in Wellington, Central Otago and Taupo use the technology.

Starting next month, National Radio plans to create national FM broadcasts of its programme. It plans to use the RDS technology to provide seamless "links" so that as a car moves out of the signal reach of one FM station broadcasting National Radio, the receiver will automatically scan other frequencies for the same programme and switch, so there is no break in reception or need to hunt for the new frequency.

ZM's use of RDS use has triggered a minor controversy on the internet, after Auckland University of Technology broadcasting lecturer Andrew Dubber posted on his website a complaint by a former student that his new radio appeared to have been retuned to ZM by remote control.

The former student, whom he named only as Peter, said the radio seemed to be "obsessed" with ZM: "If I listen to ZM or the Edge or (95bFM), or even AM stations, then turn it off and on, it starts on ZM. If I'm using the radio, then switch to CD, then back, it defaults to ZM.

"Even more annoying is what started a few weeks ago. Whatever station I'm on, whenever ZM has a traffic report, it jumps to ZM ... if I'm listening to a CD, and ZM has a traffic report, it jumps.

"I can't change back to CD until the report is over. Is it my stereo or is ZM actually Satan?"

Mr Dubber said RDS was now standard on all new tuners in car stereos around the world, and allowed radio stations to send text messages to display screens on the radios with information such as station identification, the name of the music playing, the name and sponsor of the show that was on, even messages about current on-air promotion.

He questioned whether a radio station was doing its listeners a service by interrupting listeners' CDs and talking at them.

And, if a station used RDS to default a stereo to its signal when it was turned on, that would be unethical, Mr Dubber said on the website.

Mr Boston said the technology was commonplace in Europe: "It's not supposed to make it jump stations, but if you are listening to a CD and you've got the 'traffic announcement' feature turned on, it will pause the CD, play you the traffic announcement on the radio, then go back to the CD".

The feature could be turned off at the push of a button on a car radio, he said.

About 700 of 5000 broadcasters employ it in the United States, where attempts have been made to use it for advertising.