Tait TM8100 mobiles Service Manual page 616

38.2.4 Rx / Tx/PTT Switch
38.2.5 Speaker / Radio / Load Switch
Portable
Mobile
616 TOPA-SV-024 Test Unit
This 2-way toggle switch is used to switch between receive and transmit mode.
When set to Rx, the PTT line is switched to high impedance.
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When set to Tx/PTT, the PTT line is pulled to ground.
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This 3-way toggle switch is used during receive audio tests to switch the audio
to the test unit speaker (Speaker), to the radio's internal speaker (Radio) or to
a dummy load consisting of R1 and R2 (Load).
Note
This switch does not disconnect the radio's internal speaker on
mobiles. If the switch is set to Speaker or Load, this simulates an
external speaker being connected in parallel to the radio's internal
speaker.
With all settings, a low level audio signal is available for testing through
the SINAD port.
When set to Speaker, only the speaker of the test unit is active.
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When set to Radio, only the speaker of the portable is active.
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When set to Load, no speaker is active. The audio signal is terminated in
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the test unit dummy load.
When set to Speaker, the speakers of the test unit and the mobile are
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both active. The speaker of the mobile cannot be disconnected.
When set to Radio, only the speaker of the mobile is active.
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When set to Load, the speaker of the mobile remains active.
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TM8100/TM8200 Service Manual
© Tait Electronics Limited November 2007