TP-Link RX-7-248 - Manual (Page 16)

1. TALKBACK OUT connector (XLR type) is balanced, transformer-isolated, and its nominal
level and impedance are +4dB and 600 ohms, respectively. The talkback output includes
the oscillator/pink noise generator signal or talkback mic input, depending on the switch
status on the module. The oscillator/pink noise generator function is used for matching
input and output levels with other associated equipment, and the talkback function is for
communication between a recording booth and the outside.
2. GROUND (GND) LIFT Switch is for pin 1, which is used to avoid ground loops that are
often caused in connection with other equipment and that may induce hum. Sliding the
ground lift switch from the NORMAL position to the LIFT position cuts ground loops and
may reduce hum. For most applications it should be set to the NORMAL position.
3. This cluster of buttons derives signals from the desired mixing busses, Group busses 1,2,3,
and 4, Foldback 1 and 2, and Echo 1 and 2, and assigns them to the talkback output.
4. This cluster of buttons selects the required testing signal from the available Pink noise and
Sinusoidal waves, 10kHz, 1kHz and 400Hz. When the oscillator is not used, the switch
must be "off".
5. OSC LEVEL control is provided for adjusting the oscillator output to the desired level.
6. OSC indicator turns on when any of the signal selector buttons is depressed.
7. TALKBACK INPUT CONNECTOR (XLR type) is balanced, transformer-isolated, and its
nominal level and impedance are —60dB and 600 ohms, respectively. An accessory
microphone is connected.
8. TALKBACK LEVEL control adjusts the microphone input level of the signal to be fed to the
mixing busses.
9. PRESS TO TALK pushbutton connects the talkback microphone signal to the mixing
busses when pressed. When the button is released, any oscillator signals which may have
been selected are fed.
Talkback Module (TBM-7)
(Fig. 9)
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