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KX-F1200
5. EXPLANATION
OF ANALOG
SECTION
BLOCK DIAGRAM
1) Function
The analog section serves as interface with the telephone line. The digital board (IC405) for transn_ission and reception of
FAX signals and reception of DTMF for remote signal detection. Switching between the digital board (IC405) and the other
sections is executed by means of a multiplexer in the NCU section. The control signals to the individual analog sections are
outputted mainly from the gate array IC1, and the status information for the various sections is also held in the gate array
IC1. Simple explanations for the various sections are given below.
2) Circuit Operation
[NCU Section]
Interface with the telephone line. This is composed of bell detection circuit, CPC detection circuit, pulse dial generation cir-
cuit, amplifier circuit for line transmission and reception, sidetone circuit multiplexer circuit, etc. See below for details.
[TAM IC (IC10)]
This is a IC for Auto Level Control and VOX detection from the line and Mic signals, voices.
The Digital TAM Unit for OGM and ICM recording and playback, the microphone, are connected this IC.
[Modem (IC405)]
This is used for FAX signal tone modulation, DTMF signal transmission,
and reception and line transmission beep genera-
tion.
[Speech Network IC (IC2)]
This is special IC combining the hands-free and handset circuits in 1 chip. The handset and microphone are connected to
this circuit. At the time of hands-free operation, the SP output is outputted after passage through the power amplifier (IC12)
and the key tone and the pulse dial monitor tone output from IC404 (Digital Board) and IC1 (Analog Board) are given as input
to this IC and become the monitor tone at the time of hands-free handset dialing.
[Cross Point Mixer IC (IC3)]
This IC combines 6 input analog signals and 6 output analog signals conveniently
with using 36 switches.
This connects signals of 2 lines and ITS and TAM signals, and determines signal circuit. Switch control is conducted by serial
data from IC1.
[DTMF Generator IC (IC4)]
This generates DTMF signal, and is controlled by IC1.
This is added for the case of using2 linesat the same time (e.g. Line1:Tel, Line2:FAX).
When dialing with handsetor speaker-phone,DTMF isdialed by thisIC. In the case of FAX, it is dialed by Modem.
[Voice Synthesizer IC (IC6)]
This IC has a voice message.
Message:
"Hello, no one is availableto take your call now, and our machineis busy on anothercall, please call back in a few minutes.
Thank you."
While one line is busy for receiving TAM or FAX, this machine plays this message for TAM or FAX on another line.
[In Use Detect Section]
This section checks line voltage of Line1 and Line2, and detect ON-HOOK or OFF-HOOK of paralleled telephones.
This is constructed by a line voltage detection unit, a detected voltage change unit and a power supply unit (DC-DC con-
verter).
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