JBL Ceiling Loudspeakers Owner's Manual page 9

Guide to the Pins for Connection -- The removable locking input connector
contains 4 terminals, as marked on the connector. The pin functions are listed on
the label located on the terminal cover plate.
+
Loop
Thru
Pins 2 & 3 are the "+" and "-" inputs to the loudspeaker. Pins 2 & 3 are looped to
pins 1 & 4, respectively (Pin 1 connects to Pin 2 and Pin 3 connects to Pin 4) inside
the speaker. Pins 1 & 4 are intended as loop-through connections to subsequent
loudspeakers. There are two possible hookup schemes for connecting subsequent
speakers, determined by the desired result from the circuit whenever this speaker's
connector gets disconnected during troubleshooting:
Paralleling Input Terminals -- Connect the wire pair of the subsequent
speaker to pins 2 & 3 (in parallel with the input wire pair). Whenever the
connector is pulled out of the speaker for troubleshooting, subsequent speakers
will stay connected. This can be useful during troubleshooting to be able to
disconnect a single loudspeaker at a time. In this hookup scheme, no wires get
connected to pins 1 & 4.
Figure 7:
Paralleling Input Terminals
From Amplifier or
Previous Speaker
Figure 8:
Parallel System
Hookup Diagram
Power Amplifier
8
CONNECTION
1 2 3 4
–
Loop
+
–
Thru
IN IN
1 2 3 4
+
–
1 2 3 4
+ –
Speaker 1
Figure 6: Connector Pins
–
To Subsequent
+
Speakers
1 2 3 4 1 2 3 4
Speaker 2 Speaker 3
+
To
Subsequent
–
Speakers