A battery back up unit (BBS) also known as a UPS (uninterruptible power supply) is the device that keeps your router (and therefore your telephone service) active during a power outage…its relatively unimportant what manufacturer is supplying it or what it looks like , search BBS /UPS for images if necessary, but basically your router connects to the BBU , the BBU connects to the mains , should the mains fail , the battery within the BBU takes over running the router until the mains is restored or the battery goes flat .
Presumably you have been identified as vulnerable if you have been supplied with extra equipment and an engineer visit arranged to help you convert to DV , something that the overwhelming majority do without any assistance, as its for most as simple as moving the phone cord from the wall socket to the router socket …….do you need this extra help ?, why do BT think you do if this visit isn’t (in your view ) necessary ?
