About 4.7 million subscribers of US carrier Cingular Wireless with older phones will have to pay $5 extra each month as the company tries to prod them to get new handsets so it can devote its entire network to one type of signal, according to an Associated Press report.
The report said the new surcharge, unique among the major US carriers, would be added to bills starting in September.
Cingular, jointly owned by prospective merger partners AT&T and BellSouth, reported earlier this month that roughly 92% of its 57.3 million customers used phones based on the globally dominant technology known as GSM.
The rest had handsets based on one of two older technologies.
One dates back two decades to the first-generation of mobile phones, which used an "analog," or non-digital, signal to transmit calls. The second is a digital transmission technique known as TDMA, the report said.
The new fee, which would generate $23.5 million a month for Cingular, plus the confusing array of surcharges and government taxes, regardless of the wireless company, could boost the average cellular bill by up to 50% from the advertised rate, the report further said.