GAI-Tronics 370-202, 372A Interface Amplifier Assembly for Electro-Sound - Manual (Page 3)

Pub. 42004-374A
Model 370-202 Interface Amplifier Assembly for Electro-Sound Page: 3 of 9
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07/05
Wiring a Model 370-202 Between a Page/Party ® System and an Electro-Sound II System
Figure 2 shows the wiring of a three-wire Electro-Sound system interfaced to a five-party Page/Party
®
system. Handsets or headsets plugged into jack stations are normally tied to party line 5 but switch to the
page line whenever the page switch on the handsets or headsets is pushed. The power source contains a
relay that disconnects the coupling when no handset or headset is plugged in and another relay for
switching between page and party lines.
The wiring shown in Figure 2 provides ac power to Model 471 Electro-Sound Power Source, Model 370-
202 Interface Amplifier Assembly, and Page/Party
®
wall stations.
The wiring to the interface shown in Figure 2 can be modified for two-wire Electro-Sound systems. See the
Electro-Sound installation manual, 42004-072. It is absolutely necessary to place a 33-ohm load between
points four and five or between points six and seven on the power source enclosure terminal blocks if these
points are not connected to a page or party system. The two-way amplifier in the Model 370-202 may
oscillate if these resistors or the Page/Party
® Line Balance Assembly is not connected to the Model 370-
202 Interface.