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C.5  External Input/Output Port Wiring
C.5.1  EXTERNAL INHIBIT/OVERRIDE USING A DRY CONTACT
C.5.2  EXTERNAL INHIBIT/OVERRIDE USING A DC SIGNAL
C.5.3  TEMPBUS AND INHIBIT MASTER/SLAVE CONNECTIONS
Terminal board
+9Vdc nom
External dry contact
(Close to activiate inhibit or override mode)
(2kΩ max total loop resistance)
Common
Ext. contact
Input
1
20
+
–
21
2
Terminal board
+9Vdc nom
+5VDC to 24VDC nominal, 10ma. max
Common
Ext. contact
Input
1
20
+
+
–
–
+
–
21
2
Terminal board
Terminal board
Terminal board
“Slave” 920 controller #2
“Slave” 920 controller #1
“Slave” 920 controller #25
Ext. contact
Output
Terminal board
Ext. contact
Input
Ambient sensing “master” 920 controller
Ext. contact
Input
20
5
4
21
20
21
+
–
Ext. contact
Input
20
21
+
–
Ext. contact
Input
20
21
+
–
+
–
+
–
Up to 25 “slave” 920 controllers (50 points) 
may be tied to one “master” 920 controller.
Note that the “master” and “slave” 
controllers must be installed within the 
same enclosure.