Total Access Battery Backup System (Wall or Rackmount) - 48 Volt ADTRAN designed battery backup Up to Eight hours uptime Designed for use with Total Access 612 616 624 750 850 912 916 or 924 Requires use of AC power supply battery charger (1175043L2) when used with the Total Access 750 or 850 Mounting brackets available (1200626L1) for mounting a Total Access 612 616 or 624 to this Battery Backup System (1175044L1) 19in. rackmount brackets available (PN: 1175047L1) 23in. rackmount brackets available (PN: 1175048L1) Replacement battery available (PN: 1975044L1)