80 TOPA-SV-024 Test Unit TM8000 Mobile Radio Accessories ManualMarch 2004 © Tait Electronics Limited10.2.4 Rx / Tx/PTT switchThis 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. When set to Tx/PTT, the PTT line is pulled to ground.10.2.5 Speaker / Radio / Load switchThis 3-way toggle switch is used during receive audio tests to switch the audioto the test unit speaker (Speaker), to the radio’s internal speaker (Radio) or toa dummy load consisting of R1 and R2 (Load).Note This switch does not disconnect the radio’s internal speaker onM8100 radios with a user interface. If the switch is set to Speakeror Load, this simulates an external speaker being connected in par-allel to the radio’s internal speaker. TM8100 radios without a userinterface do not have an internal speaker.With all settings, a low level audio signal is available for testing throughthe SINAD port.Tait Orca portables When set to Speaker, only the speaker of the test unit is active. When set to Radio, only the speaker of the Tait Orca portable is active. When set to Load, no speaker is active. The audio signal is terminated inthe test unit dummy load.TM8100 radios withuser interface When set to Speaker, the speakers of the test unit and the TM8100 areboth active. The speaker of the TM8100 cannot be disconnected. When set to Radio, only the speaker of the TM8100 is active. When set to Load, the TM8100 speaker remains active.
