The growth of fibre optic networks has left watchdog Ofcom demanding that companies fit battery backups supplying one hour of phone service – because without the copper wire phone system people would not be able to make calls in the event of a power cut.

Although fibre brings myriad improvements, one drawback is that a lack of power cripples the system – a problem that did not hit the old copper cabling setup.

"A conventional telephone draws the necessary power for operation from the local exchange via the copper telephone wires, and as a result can continue to function even when there is a power cut at the premises," explained Ofcom.

Need more power captain

"However, optical fibres are unable to support this arrangement as they do not conduct electricity. The consequence of this limitation in fibre optic networks is that, if there is a power failure at the property, and absent any other measures being taken, the telephone will stop working. Hence calls, including calls to the emergency services, are not possible."

Ofcom's answer is to install a battery backup system – and it believes that one hour of battery backup is enough.

"In practice, a back-up supply of power to ensure that calls can be made over optical fibre networks during a power cut is normally supplied via a battery installed at the customer's premises," added Ofcom.

"The question that arises from solutions of this type is the length of time over which the battery back-up remains operational."

"Given the expected growth in fibre optic networks over the next few years and in light of recent survey evidence that suggests that communications providers are adopting a mix of power back-up solutions in their current deployments, we believe that this represents an appropriate time to address this issue."