UBR1221A module is designed to receive a single pair of Audio signal from CSP products, and transfers the signal to the Balanced or Unbalanced Audio Output on the front panel. Set the switch on the front panel to determine which pair of UTP CAT 5 cable to receive the signal and goes to the output of this module. 
UBR1221A module only receives one pair of CAT5 cable by setting the switch, this means UBR1221A accepts 3 pairs of signals from other CSP transceivers to RJ45 Input jack, the additional CSP Receivers could be chained to the LOOP OUT jack. The other two single pair of CSP receivers could be chained together with UBR1221A, or a single two pair of receiver could be connected. By using same pair of CAT5 cable, the additional CSP receivers could be chained together to distribute same signal to different locations.
UBR1221A module is passive and does not require the DC power. If the DC power presents on RJ45 LOOP OUT or INPUT jack, the DC power is pass through to the connected CSP products.