Battery backup system

The item concerned is referrd to as
a Battery Backup System (BBS) 6102, part number 20/BFM901292/895.

The BBS 6102 is an electrically outfitted
cabinet. It is used to house and recharge backup batteries and to supply
(negative) -48 volt DC power to outdoor radio base stations and remote radio
units in the event of AC mains failure. 

The BBS 6102 is powered by AC
current from the grid. The BBS 6102 houses power supply units / rectifiers that
are responsible for converting AC to DC power, recharging the internal
batteries and powering the connected remote radio units and radio base

The applicable subheading for the Battery
Backup System (BBS) 6102 will be 8504.40.

Source:,  December 19, 2017 (N292646)