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The general ITS operation is performed by IC200 which has a handset circuit. The alarm tone, the key tone, and the beep are
output from Soc IC300.

1. Function

This is the function when you are not holding the handset and can hear the caller’s voice from the line.

2. Circuit Operation

(Telephone Monitor Signal Path)
Signals received from the telephone line are output through at the speaker via the following path.

3. Signal Path

TEL LINE

→D103→Q104→C106→IC101(3-5,6)→IC100(9,10-5)→IC300(AD26-AB24)→IC200(4-1)→IC202(2-1)→IC204(4-

5,8)

→CN200(1,2)→CN58(1,2)→CN57(1,2)→SPEAKER

1. Function

This circuit controls the conversation over the handset, i.e. the transmitted and received voices to and from the handset.

2. Signal Path (Transmission signal)

OPTION HANDSET UNIT

→CN58(5,6)→CN200(5,6)→IC202(5,6-7)→IC201(3-5)→IC200(10-5)→IC300(AB25-

AC24)

→IC100(6-9,10)→IC101(5,6-3)→C106→Q104→D103→TEL LINE

3. Signal path (Reception signal)

TEL LINE

→D103→Q104→C106→IC101(3-5,6)→IC100(9,10-5)→IC300(AD26-AB24)→IC200(4-16)→IC203(4-

8)

→CN200(7,8)→CN58(7,8)→OPTION  HANDSET UNIT

1. Function

This circuit monitors various tones, such as (1) DTMF tone, (2) Alarm/Beep/Key tone/Bell.

2. Signal Path

a. DTMF Monitor

(Speaker Operation)
IC300(AB24)

→IC200(4-1)→IC202(2-1)→IC204(4-5,8)→CN200(1,2)→CN58(1,2)→CN57(1,2)→SPEAKER

(Handset Operation)
IC300(AB24)

→IC200(4-16)→IC203(4-8)→CN200(7,8)→CN58(7,8)→OPTION  HANDSET UNIT

b. ALARM/BEEP/KEY TONE/BELL

IC300(B20)

→IC202(2-1)→IC204(4-5,8)→CN200(1,2)→CN58(1,2)→CN57(1,2)→SPEAKER

1. Function

When TAM is connected to this unit, the unit receives documents for FAX calls or the external TAM records a voice message
automatically.

2. Circuit Operation

The TAM INTERFACE circuit consists of Soc(IC300) to detect the other party CNG signal, and RLY100 to separate EXT.TAM.

a. CNG signal detection circuit

The CNG signal from the other party’s FAX is detected in Soc IC300 
(Signal path)
TEL LINE

→IC101 (8,9 - 5,6)→IC100 (9,10 - 5)→IC300(AD26)

b. Remote receiving

This is the parallel-connected DTMF signal for the TEL or EXT.TEL mode between T and R. When the other party is a
FAX, the unit switches to FAX receiving.
(Signal Path)
TEL LINE

→IC101 (8,9 - 5,6)→IC100 (9,10 - 5)→IC300(AD26)

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The scanning block of this device consists of a control circuit and a CIS (contact image sensor), and AFE (Analog Front End) includ-
ing A/D Converter.

When an original document is inserted and the start button is pressed, pin A3 of IC300 goes to a low level and the transistor Q503
is turned on. This applies voltage to the CIS. The CIS is driven by each of  the CCDSH , CCDCLK  signals output from IC300, and
the original image illuminated by the LED to output an analog image signal. 
The analog image signal is input to the AFE on VINP(20pin of IC500) and converted into 16-bit data by the A/D converter inside
IC500. Then this signal undergoes digital processing in order to obtain a high-quality image.

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1. Functions

This circuit is used for driving the BK motor which supplies the rotation to the monochrome drum cartridge, black toner car-
tridges, accumulator unit, paper feed unit ,and fuser unit. The BK motor control signals are explained as follows.

2. Circuit Operation

NITMON :

This signal is the control signal for the BK motor. To rotate the BK motor, IC600 outputs the low level NITMON from pin 
H20 of IC600 to IC760 (pin 1). This signal is sent to the BK motor control circuit through IC760, connector CN760. When 
the signal NITMON (pin 6 of CN760) becomes a low, the BK motor starts to rotate.

ITMCLK :

This is the external clock for the BK motor. At 600 dpi monochrome printing and color printing, this value is 1656.01 Hz
(1987.212 rpm). At 1,200 dpi monochrome printing and color printing, this value is 667.7458 Hz (801.295 rpm). 

NITMLD :

This is the BK motor speed detection signal sent from the BK motor drive in the BK motor. The BK motor is kept at a con-
stant speed (600 dpi printing : 1987.212 rpm, 1,200 dpi printing : 801.295 rpm). When the BK motor speed is not a proper
constant speed, this NITMLD signal (pin 5 of CN760) is a high. IC600 receives this high level NITMLD signal, and the error
message “CALL SERVICE 5” is displayed on the LCD display. (Refer to CALL SERVICE 5) (P.187)

ITMG :

This is the BK motor gain control signal to control the BK motor speed. This signal ITMG is sent from pin J18 of IC600 to
the BK motor through IC760 and connector CN760. When pin 8 of connector CN760 is a low, the gain adjustment for 600
dpi printing mode is done by the BK motor drive circuit in the BK motor. When pin 8 of CN760 is a high, the gain adjust-
ment for 1,200 dpi printing mode is done.  

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3. Sequence Control

1.  Functions

This circuit is used for driving the color motor which supplies the rotation to the color drum cartridge and color toner cartridges.
The color motor control signals are explained as follows :

2. Circuit Operation

NPCMON :

This signal is the control signal for the Color motor. To rotate the Color motor, IC600 outputs the low level NPCMON from
pin L20 of IC600 to IC760 ( pin 9 ). This signal is sent to the Color motor control circuit through IC760, connector CN761.
When the signal NPCMON ( pin 6 of CN761 ) becomes a low, the Color motor starts to rotate.

PCMCLK :

This is the external clock for the Color motor. At 600 dpi color printing, this value is 1656.01 Hz ( 1987.212 rpm ). At 1,200
dpi color printing, this this value is 667.7458 Hz ( 801.295 rpm ).

NPCMLD :

This is the Color motor speed detection signal sent from the Color motor drive in the Color motor. The Color motor is kept
at a constant speed ( 600 dpi color printing : 1987.212 rpm, 1,200 dpi color printing : 801.295 rpm ). When the Color motor
speed is not NPCMLD signal, and the error message “CALL SERVICE 12” is displayed on the LCD display. (Refer to
CALL SERVICE 12 (P.190)

PCMG :

This is the Color motor gain control signal to control the Color motor speed. This signal PCMG is sent from pin J20 of
IC600 to the Color motor through IC760 and connector CN761. When pin 8 of connector CN761 is a low, the gain adjust-
ment for 600 dpi printing mode is done by the color motor drive circuit in the color motor. When pin 8 of CN761 is a high,
the gain adjustment for 1,200 dpi printing mode is done.