Read Panasonic KX-TCD755RUS Service Manual online
7.1.6. Locator Key (See Fig. 18)
The Locator (Page) button is connected to pin 87 (TP109) of the IC6. When pressed the base transmits a message to the
handset, which then beeps.
handset, which then beeps.
7.1.7. Factory Serial Port (See Fig. 18)
In order to communicate with the base band section during manufacture and servicing (using a PC) a serial data link has been
provided.
Serial data input/output is provided through the SDA terminal (J102). The data is clocked through using the SCL terminal
(J103). A ground terminal is provided by J104.
To invoke the external communication mode the MODE_SEL terminal (J101) must be connected to the 2.65V terminal (J100).
The serial port terminals J100 to J104 are connected to by means of test probe pads on the ground plane side of the pcb.
provided.
Serial data input/output is provided through the SDA terminal (J102). The data is clocked through using the SCL terminal
(J103). A ground terminal is provided by J104.
To invoke the external communication mode the MODE_SEL terminal (J101) must be connected to the 2.65V terminal (J100).
The serial port terminals J100 to J104 are connected to by means of test probe pads on the ground plane side of the pcb.
7.1.8. Buzzer Circuit (See Fig. 18)
A square-wave signal from IC6 pin 71 is used to sound the buzzer via switching transistor T6 (TP98). Various tones and
cadences are used dependent on function. Buzzer volume is varied by changing the duty cycle of the drive waveform. D16
provides quenching of back-emf generated when T6 turns off.
cadences are used dependent on function. Buzzer volume is varied by changing the duty cycle of the drive waveform. D16
provides quenching of back-emf generated when T6 turns off.
7.1.9. Audio Path - Rx Audio - Line Input (See Fig. 18)
Audio from the line interface TXAF (TP97) enters the BBIC on pin 43. The audio signal passes through the analogue part of the
BBIC where it is amplified and converted to a digital audio stream signal. The burst mode controller processes this stream
performing encryption and scrambling, adding the various other fields to produce the GAP standard DECT frame, assigning to
a time slot and channel etc. to emerge on pin 15 as TXDA.
BBIC where it is amplified and converted to a digital audio stream signal. The burst mode controller processes this stream
performing encryption and scrambling, adding the various other fields to produce the GAP standard DECT frame, assigning to
a time slot and channel etc. to emerge on pin 15 as TXDA.
7.1.10. Audio Path - Tx Audio - Line Output (See Fig. 18)
Audio from the receiver RXDA enters the BBIC on pin 8 as GAP standard DECT frames. It passes through the decoding section
burst mode controller where it separates out the frame information and performs de-encryption and de-scrambling as required.
It then goes to the DSP where it is turned back into analogue audio. This is amplified by the analogue front end and emerges
at pin 37 - i.e. the RXAF signal of the line interface.
burst mode controller where it separates out the frame information and performs de-encryption and de-scrambling as required.
It then goes to the DSP where it is turned back into analogue audio. This is amplified by the analogue front end and emerges
at pin 37 - i.e. the RXAF signal of the line interface.
17
KX-TCD755RUS
Click on the first or last page to see other KX-TCD755RUS service manuals if exist.