The breakdown in SmarTone's mobile coverage on Monday was caused by a back-up power generator in Sha Tin restarting itself repeatedly, the telecoms operator said yesterday.
SmarTone, a subsidiary of Sun Hung Kai Properties, is facing a barrage of criticism and a possible fine from telecoms watchdog Ofca after a quarter of its mobile network coverage failed.
The breakdown cut services to thousands of users on Hong Kong Island and at some train stations in Kowloon.
The 21/2-hour power failure at the Sha Tin switchboard station, one of three SmarTone has across the city, affected 25 per cent of its cell sites, it said in a preliminary report submitted to Ofca.
Cell sites are locations where antennas and other electronic communications equipment are placed. The operator did not reveal the total number of affected customers.
'It is difficult to estimate ... due to the mobility of users and the lack of [previous] reference to a non-working day within a long holiday,' the report said.