Television screens of people, who have not switched to digital set top boxes as mandated by Telecom Regulatory Authority of India (TRAI), will go blank in Patna and the rest of the state from Friday.

According to the records of the ministry of information and broadcasting, around 4 lakh television sets in Bihar, including 60,000 in Patna district, might face blackout from Friday as they have not installed digital set- top boxes.

According to the directives, beaming of analogue television signal has to stop and digital beaming has to start from January 1. The ministry issued an advisory in this regard on Wednesday, asking the multi-system operators to follow the December 31 deadline.

"We would stop beaming analogue signals in Tier 3 cities, including Phulwarisharif, Danapur, Khagaul and Fatuha among others from Friday," said Rajnish Dikshit, the director of SITI Maurya Cablenet Pvt. Ltd. Sushil Kumar, director, Darsh Digital Network Pvt. Ltd. claimed that only around 20 per cent of TV sets at places under phase-3 have been installed with digital set-top boxes. "Monthly expenses of Rs 10,000 on optical fibre to beam digital signals is exorbitant for us in rural areas," he said.