Panasonic KX-TS105LXW, Service Manual, Page: 17 / 44

Pin
NO.
Name
Description
22 Gnd Ground pin for the IC (except the speaker amplifier).
23 XDC Transmit detector output. A resistor and capacitor at this pin hold the system in the transmit
mode during pauses between words or phrases. When the XDC pin voltage decays to ground,
the attenuators switch from the transmit mode to the idle mode. The internal resistor at
nominally 2.6 kohms.
24 VLC Volume control input. Connecting this pin to the slider of a variable resistor provides receive
mode volume control. The VLC pin voltage should be less than or equal to VB.
25 ACF Attenuator control filter. A capacitor connected to this pin reduces noise transients as the
attenuator control switches levels of attenuation.
26 RXO Output of the receive attenuator. Normally this pin is ac coupled to the input of the speaker
amplifier.
27 RXI Input of the receive attenuator. Input resistance is nominally 5.0 kohms.
28 RRX A resistor to ground determines the nominal gain of the receive attenuator. The receive
gain is directly proportional to the RRX resistance.
8. TERMINAL GUIDE OF IC’S TRANSISTORS AND
DIODES
17