Uninterruptible Power Supply (UPS)
An uninterruptible power supply is equipment that keeps electrical equipment running from batteries during a mains power failure.
What is Uninterruptible Power Supply (UPS)?
Network sites and cabinets use UPS units to maintain service during short outages and allow orderly switch-over to generators. Battery back-up has become a regulatory topic in the UK as phone services move from copper (powered by the exchange) to fibre and VoIP (powered at home).