Figure 3-1 Connections For Multiple Audio Booster In Two-Wire Mode (Spb-160) - Wheelock SAFEPATH4 Application, Installation, Operation, And Maintenance Manual

Connections for Multiple Audio Booster in Two-Wire Mode
The Four Wire Audio Mode is used when multiple Audio Boosters are used on the output of the
SP40/2 and it is not desirable to lose secondary operations when a single audio booster goes into
trouble. Only that Audio Booster will lose secondary operations. An 8-33VDC NAC or a contact
closure applied to the AUX IN terminals will energize the Audio Booster on battery backup and
have it broadcast the message.
Connecting 1 to 33 Audio Booster panels to an SP40/2 in the four wire mode is done by
connecting the audio output (AUD OUT) from the SP40/2 to the master Audio Booster panels
audio input (AUD IN). The UL Listed 10K Ohm EOLR shall be placed on the last Audio Booster
AUD RET. Connecting multiple Audio Booster panels is illustrated in Figure 3-1.
SP40/2
AUD OUT
UL Listed
10K Ohm
EOLR
Figure 3-1
AUDIO
BOOSTER
Closed
W1
Closed
W10
AUD IN
AUD RET
AUDIO
BOOSTER
Closed
W1
Closed
W10
AUD IN
AUD RET
AUDIO
BOOSTER
Closed
W1
Closed
W10
AUD IN
AUD RET
20