Battery Reversal FXS & Dial Pulse Origination Card
9-22 9/24/01
9.7 Setting BRFXS and DPO

9.7.1 Battery Reversal FXS Loop-Start

The BRFXS/DPO card includes a setting for 2-wire FXS loop-start operation with battery reversal.
To enable this option, set Switch A on the 4-position DI P s wit ch t o ON s o t hat cadenced ringing volt-
age is applied to the CPE loop during an incoming call (See T able 9-2 ). The batt ery is r eversed dur ing
this time. If desired, Switch B can be turned ON also to send a cadenced (2-second/ 4-second) ring-
back tone to the T1 line during incoming calls.

9.7.2 Dial Pulse Origination (DPO)

The DPO option is selected by setting Switch A to OFF so that no ringing voltage is applied towards
the CPE. If desired, Switch B can be turned ON to give a cadenced (2 second/ 4 second) ringback
tone to the T1 line during incoming calls (See Table 9-2) . To indicate an incoming call, the battery to
the CPE loop is reversed. When the call ends, the battery returns to forward.

9.7.3 BRFXS/DPO Voice Channel Monitoring and Testing

The channel status LEDs on the back plate of the Access Bank II al low you to monitor the individual
BRFXS/DPO voice lines. The meaning of these LEDs is summarized above in Figure 9-4.
The channel test switches on the BRFXS/DPO back plate can be used to apply reverse battery to the
CPE loop and send A/B bits forced to 1/1 toward the T1 network. If Switch A is ON, 4 seconds of
continuous ringing voltage (85 V) are sent to the tip and ring pair of each BRFXS/DPO voice chan-
nel. In this case, you can check the operation of an individual voice channel by attaching a test tele-
phone to the Tip and Ring pair of that particular channel at the punchdown block or RJ-11
Harmonica, then switching ON the appropriate channel test switch to test that channel. If Switch B is
ON, 4 seconds of continuous ringback tone is also sent to the T1 network.
9.8 Busying Out Individual BRFXS/DPO Channels
If Switch A and Switch B are both ON, setting a channel test switch to ON has four results on the
selected channel:
1. Reverse battery is applied to the CPE loop and th e A/B si gnaling bits sent to the network are
forced to 1/1.
2. To confirm individual channel circuit integrity, 4 seconds of continuous ringing voltage are
sent to the Tip and Ring pair. The Tip is the n gr ounde d unt i l t he channel test switch is turned
to the OFF position (to the right).