Samsung SCX-4521F Series Service Manual page 24

3) CIS Driving Part
- CIS Supply Voltage : +3.3V
- CIS Max frequency : 5MHz
- CISLinetime
Fax/Copy - 1.5ms
PC-Scan - 4.5ms
- White output volt. : Max 0.8V
4) ADF Driving Part : Driving ADF Stepper motor, and the maximum motor speed is 2000PPS.
- MOTOR DRIVER : A3978(Allegro)
- Driving Voltage : 24V DC
- Phase : 2-2 Phase 2000PPS at Quick Scan,
2-2 Phase 1000PPS AT Fine Scan,
2-2 Phase 667PPS AT Super Fine Scan
3.2.3 Fax Modem Part
1) Modem Part
The modem part is consist of FM336(FAX Modem chip), LIU(Line Interface Unit) and modem analog front
end(AFE) functional part.
- The feature of the FM336 modem chip is as below;
Communication Mode : Half Duplex
Modem Method
GROUP 3 : ITU-T V34, V17, V29, V27ter
Tonal Signal : ITU-T T.30
Binary Signal : ITU-T V.21, T.30
Image Transmission Time : 3sec ( ITU-T NO.1 CHART/Memory Tx/ECM )
Data Compress : MH, MR, MMR, JPEG
Modem Speed : 33600 / 28800 / 14400 / 12000 / 9600 / 7200 / 4800 / 2400 bps
Receive Level : 0 ~ -48dBm
Output Level
Adjustable : -6 ~ -15dBm ( 1dBm Step )
Initial Setting : -12dBm
Receive dynamic range:
0 dBmto-43 dBmfor V.17,V.29,V.27 ter and V.21
-9 dBm to -43 dBm for V.34 halfduplex
2) The Gain of the Line signal can be adjusted by setting the register value of the FAX modem chip ,Tx and Rx path
is almost directly connected to the impedance matching transformer of the LIU.
- Adjust Tx Level within Setting Level+0,-2dB range.
- Adjust Rx Level that has the same level as the TIMS out level if possible, and must not exceed the TIMS
out level.
3) Speaker Driving Part
Analog Switch(MC14053BD) makes a path for FAX Tone, Ring, Key click sound and Analog MUX
(MC14051) makes a different signal level so that the the Speaker driver chip(MC34119) can driving the
Speaker with different sound volume.
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System Overview
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