7700FR/7800FR MultiFrame
7800TR-32x24 Modular Tally Router
Revision 1.2
Page -
19
GPO A
GPO B
0.15A max
DRY GPO
1
2
Relay
Figure 3-9: 7800TR-BHP GPO in Dry Mode Circuit Diagram
3.9.2 7800TR-BHP General Purpose Input Connections
The rear 24 General Purpose Inputs from the tally router are broken out to 24 terminal blocks across
the bottom of the bulkhead panel. Each GPO has a miniature slide switch below it to select between
Wet and Dry modes (see section 3.8.1). The circuit diagrams for the GPIs in both modes are shown in
Figure 3-10 and Figure 3-11.
GPI +
GPI -
~10 mA
~1.4 V
WET GPI
1
2
optoisolator
Figure 3-10: 7800TR-BHP GPI in Wet Mode Circuit Diagram
~10 mA
+WET
DRY GPI
1
2
GPI +
~1.4 V
GPI -
WET-
Figure 3-11: 7800TR-BHP GPI in Dry Mode Circuit Diagram
