8.6.2. Modem Circuit Operation
The modem (IC505) has all the hardware satisfying the ITU-T standards mentioned previously.
When the ASIC IC501 (61) is brought to a low level, the modem (IC505) is chip-selected and the resistors inside IC are selected
by the select signals from ASIC (IC501) ADR0-ADR4(pin 83~87). Commands are written through the data bus, and all processing
is controlled by the ASIC (IC501) according to ITU-T procedures. Here, the INT signal dispatched from IRQ (pin 60 of IC505) to the
ASIC (IC501) implements post processing.
This modem (IC505) has an automatic application equalizer. With training signal 1 or 2 at the time of G3 reception, it can
automatically establish the optimum equalizer. The modem (IC505) clock is supplied by pin 55 of ASIC (IC501).
1. Facsimile Transmission/DTMF Line Send
The digital image data on the data bus is modulated in the modem (IC505), and sent from pin 69 via, Analog SW IC520(8
→
9),
amplifier IC521(6
→
7) and the NCU section to the telephone line.
Refer to Check Sheet(P.126).
2. Facsimile Reception
The analog image data which is received from the telephone line passes through the NCU section and enters pin 60 of the
modem (IC505). The signals that enter pin 60 of the modem (IC505) are demodulated in the board to digital image signals, then
placed on the data bus.
In this case, the image signals from the telephone line are transmitted serially. Hence, they are placed on the bus in 8 bit units.
Here, the internal equalizer circuit reduces the image signals to a long-distance receiving level.
This is designed to correct the characteristics of the frequency band centered around 3 kHz and maintain a constant receiving
sensitivity.
It can be set in the service mode.
Refer to Check Sheet(P.126).
3. DTMF Transmission (Monitor tone)
The DTMF signal generated in the modem (IC505) is output from pin 69, and the NCU section to the telephone line the same
as facsimile transmission signals.
(DTMF Monitor Tone)
Refer to Check Sheet(P.126).
4. Busy/Dial Tone Detection
The path is the same as FAX receiving. When it is detected, the carrier detect bit of the resistor in the modem (IC505) becomes
1, and this status is monitored by ASIC (IC501).
175
KX-FC379CX
Summary of Contents for KX-FC379CX
Page 38: ...6 2 3 How to Remove the Operation Board and LCD 37 KX FC379CX ...
Page 39: ...6 2 4 How to Remove the Image Sensor CIS 38 KX FC379CX ...
Page 40: ...6 2 5 How to Remove the Thermal Head 39 KX FC379CX ...
Page 41: ...6 2 6 How to Remove the Back Cover 6 2 7 How to Remove the Platen Roller 40 KX FC379CX ...
Page 42: ...6 2 8 How to Remove the Pickup Roller and Antenna 41 KX FC379CX ...
Page 44: ...6 2 11 How to Remove the Digital Analog and Sensor Boards 43 KX FC379CX ...
Page 45: ...6 2 12 How to Remove the Power Supply Board and AC cord 44 KX FC379CX ...
Page 46: ...6 2 13 How to Remove the Gear Block and Separation Roller 45 KX FC379CX ...
Page 47: ...6 2 14 How to Remove the Gears Motors and Arms of the Gear Block 46 KX FC379CX ...
Page 48: ...6 2 15 Installation Position of the Lead Wires 47 KX FC379CX ...
Page 49: ...6 2 16 How to Remove the Antenna of Handset 48 KX FC379CX ...
Page 50: ...6 2 17 How to Remove the Handset Board and LCD 49 KX FC379CX ...
Page 51: ...6 2 17 1 Assembly the LCD to Handset Board 50 KX FC379CX ...
Page 63: ...7 4 4 1 Test Burst Mode and Test TX CW Mode 62 KX FC379CX ...
Page 64: ...7 4 4 2 RX CW Test Mode 63 KX FC379CX ...
Page 65: ...7 4 4 3 Test Link Mode 64 KX FC379CX ...
Page 66: ...7 4 5 Test Mode Flow Chart for Handset 7 4 5 1 TX Burst Mode 65 KX FC379CX ...
Page 67: ...7 4 5 2 RX CW TEST Mode 66 KX FC379CX ...
Page 79: ...7 6 2 Service Mode Settings Note The above values are the default values 78 KX FC379CX ...
Page 94: ...93 KX FC379CX ...
Page 108: ...107 KX FC379CX ...
Page 109: ...CROSS REFERENCE TEST FUNCTIONS P 58 108 KX FC379CX ...
Page 110: ...CROSS REFERENCE TEST FUNCTIONS P 58 109 KX FC379CX ...
Page 111: ...CROSS REFERENCE TEST FUNCTIONS P 58 110 KX FC379CX ...
Page 112: ...CROSS REFERENCE TEST FUNCTIONS P 58 111 KX FC379CX ...
Page 113: ...112 KX FC379CX ...
Page 114: ...113 KX FC379CX ...
Page 115: ...CROSS REFERENCE TEST FUNCTIONS P 58 114 KX FC379CX ...
Page 119: ...118 KX FC379CX ...
Page 123: ...I O and Pin No Diagram 122 KX FC379CX ...
Page 125: ...Other NG example while the power is ON and the LCD displays the following 124 KX FC379CX ...
Page 126: ...7 7 6 3 NG Example 125 KX FC379CX ...
Page 128: ...127 KX FC379CX ...
Page 131: ...Note Check to the SP Phone Rx Tx signal routes Refer to Check Sheet P 126 130 KX FC379CX ...
Page 133: ...7 7 9 2 Troubleshooting Flow Chart 132 KX FC379CX ...
Page 139: ...7 7 13 Thermal Head Section Refer to Thermal Head P 161 138 KX FC379CX ...
Page 146: ...7 7 16 1 5 RF DSP interface signal wave form 145 KX FC379CX ...
Page 148: ...8 CIRCUIT OPERATIONS 8 1 CONNECTION DIAGRAM 147 KX FC379CX ...
Page 152: ...8 3 2 Memory Map 151 KX FC379CX ...
Page 161: ...8 4 2 Block Diagram 160 KX FC379CX ...
Page 163: ...162 KX FC379CX ...
Page 201: ...8 18 EXPLANATION OF RF UNIT TERMINALS RF Unit 8 18 1 IC901 200 KX FC379CX ...
Page 202: ...9 REFERENCE MATERIAL DATA 9 1 TERMINAL GUIDE OF THE ICs TRANSISTORS AND DIODES 201 KX FC379CX ...
Page 205: ...9 3 TEST CHART 9 3 1 ITU T No 1 Test Chart 204 KX FC379CX ...
Page 206: ...9 3 2 ITU T No 2 Test Chart 205 KX FC379CX ...
Page 207: ...10 FIXTURES AND TOOLS 206 KX FC379CX ...
Page 208: ...11 CABINET MECHANICAL AND ELECTRICAL PARTS LOCATION 11 1 GENERAL SECTION 207 KX FC379CX ...
Page 210: ...11 3 UPPER CABINET SECTION 209 KX FC379CX ...
Page 211: ...11 4 BACK COVER SECTION 210 KX FC379CX ...
Page 212: ...211 KX FC379CX ...
Page 213: ...212 KX FC379CX ...
Page 214: ...11 5 LOWER CABINET P C BOARD SECTION CROSS REFERENCE GEAR BLOCK SECTION P 214 213 KX FC379CX ...
Page 215: ...11 6 GEAR BLOCK SECTION 214 KX FC379CX ...
Page 216: ...11 7 HANDSET SECTION 215 KX FC379CX ...
Page 217: ...11 8 SCREWS 216 KX FC379CX ...
Page 218: ...12 ACCESSORIES AND PACKING MATERIALS 217 KX FC379CX ...