Carrier Access Access Bank II SNMP - Manual (Page 90)

BRFXS/DPO Applications
9/24/01 9-17
Note: During a two-way call, the CPE -loop battery is reversed. To disconnect the
call either the CPE loop current ceases or the network sends A/B bits = 0/0. The
reversed state of the CPE loop, however, will be maintained until the network
terminates (releases) the call.
9.4 BRFXS/DPO Applications
As explained above, the two major applications for the BRFXS/DPO card are FXS with battery
reversal “wink” to signal a PBX timer to start billing a call and Dial Pulse Origination (DPO) for
transport of Direct Inward Dialing (DID) lines. Refer to Figure 9-1 and Figure 9-2 for pictorial repre-
sentations of these two applications.
Figure 9-1: Battery Reversal FXS Loop-Start for Starting PBX Billing Timer
DPO*
PBX
Battery Reversal to PBX
T1
Optional cadenced
ringback tone to T1 during
incoming calls Optional cadenced ringing
voltage applied to CPE
during incoming call
FXS loop-start lines