GAI-Tronics 370-201, 372A Interface Amplifier Assembly - Manual (Page 5)

Pub. 42004-019D
Model 370-201 Interface Amplifier Assembly Page: 5 of 9
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07/05
Checkout and Adjustment
1. After the Model 370-201 is installed and connected to the power, verify that normal use of the
Page/Party ® system has not been affected by the addition of the Model 370 Interface. Make sure that
the GAI-Tronics sidetone level (the amount of transmitted signal from the microphone that is heard in
the receiver) is not substantially affected when the interface is connected to the system.
If oscillation, distortion, or excessive sidetone occurs, check the Model 370 installation wiring and
ensure that the 305-001 Line Balance Assembly is properly installed and connected. See 42004-139,
the GAI-Tronics 700 Series Page/Party
®
Systems installation manual. If normal operation is not
restored, proceed to Step 3.
2. After the Model 370-201 has been connected to the Private Branch Exchange (PBX) extension, initiate
a call to the PBX extension connected to the Model 370-201 Interface and verify the ability to carry on
a conversation between the telephone system and the Page/Party
®
system.
N OTE : The Model 370-201 Interface Amplifier is designed to connect a line from a PBX to a
GAI-Tronics Page/Party ® system. It is designed to match impedance and voltage levels of the 600-ohm
0 dBm telephone network and the 33-ohm 18 dBm GAI-Tronics system. This unit is not designed to be
connected to the Public Telephone switched Network and is not FCC Part 68-approved.
3. After system basic operation has been verified, adjust the Model 370-201 Interface if necessary. First,
establish communications between the PBX and the Page/Party ® handset station nearest the interface.
Follow Sub-steps A through C to complete the Model 370-201 adjustment. Adjustments are made
through the plugged access holes on the front cover.
A. The Balance Control is adjusted for minimum sidetone at the GAI-Tronics station. To perform
this adjustment, blow into the microphone of the GAI-Tronics handset and adjust the balance
potentiometer on the Model 370-201 Interface to “null out” the microphone signal from the
receiver.
B. Adjust the Line to GAI-Tronics potentiometer until the volume of the voice of the caller on the
PBX is comparable to normal voice levels on the GAI-Tronics system. See note below.
C. Adjust the GAI-Tronics to Line potentiometer until the volume of the signal from the GAI-Tronics
system to the PBX line is comparable to normal system voice levels. See note below.
N OTE : If the LINE TO GTC and/or the GTC TO LINE controls are set too high, oscillation and
distortion may result. In this event, decrease these control settings, readjust the BALANCE
control as necessary, and reset the LINE
TO GTC and/or the GTC TO LINE controls for optimum
levels below the point at which oscillation occurs.