Matsushita Electric KX-TSC35MXW, Service Manual

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A0, A1, and A2 terminal is not used.
4. WP
WP terminal controls writing action. It is possible to do only
reading action when high level input and it is possible to do
reading and writing action when low level input.
10.5. Speakerphone IC Data (IC601)
Pin
NO.
Name
Description
1 RR A resistor to ground provides a reference current for the transmit and receive attenuators.
2 RTX A resistor to ground determines the nominal gain of the transmit attenuator. The transmit
channel gain is inversely proportional to the RTX resistance.
3 TXI Input to the transmit attenuator. Input resistance is nominally 5.0 kohms.
4 TXO Output to the transmit attenuator. The TXO output signal drives the input of the transmit
detector, as well as the external circuit which drives the telephone line.
5 TLI Input of the transmit level detector. An external resistor ac coupled to the TLI pin sets the
detection level. Decreasing this resistor increases the sensitivity to transmit channel signals.
6 TLO Output of the transmit level detector. An external resistor and capacitor set the time the
comparator will hold the system in the transmit mode after speech ceases.
7 RLI Input of the receive level detector. An external resistor ac coupled to the RLI pin sets the
detection level. Decreasing this resistor increases the sensitivity to receive channel signals.
8 RLO Output of the receive level detector. An external resistor and capacitor set the time the
comparator will hold the system in the receive mode after the receive signal ceases.
9 MCI Microphone amplifier input. Input impedance is nominally 10 kohms and the dc bias voltage
approximately equal to VB.
10 MCO Microphone amplifier output. The mic amp gain is internally set at 34 dB (50 V/V).
11 CP1 A parallel resistor and capacitor connected between this pin and Vcc holds a voltage
corresponding to the background noise level. The transmit detector compares the CP1
with the speech signal from CP2.
12 CP2 A capacitor at this pin peak detects the speech signals for comparison with the background
noise level held at CP1.
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