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Toshiba GD-1221 Line current detection circuit, REVA1, Line Current Detection Signal IC23, REVB1

Models: GD-1220 GD-1221

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4.2.4Line current detection circuit

NA/TW models

NCU board

					R87
					1	8
						PC3
					2	7
				C7
					3	6
						PC3
	CN10	4	Lb	R86	4	5
Line				R86

19

CN9

20

SG

FAX board

	19	REVA1	66
CN262				CN5
	20	REVB1	33

	MAIN board
	66	160
	CN5	IC23
	CN5	ASIC
		ASIC
	33	161

Fig. 4-8

The line current detection circuit consists of the photocoupler (PC3), ASIC (IC23) on the MAIN board and the other peripheral devices. It detects a dial tone and the hook status of the external telephone from the current flowing through the line.

When a dial tone is input from the telephone line, current flows through the line and the photocoupler is repeatedly turned ON/OFF. This allows the REVA1 and REVB1 to be the pulse signals and input to the ASIC, then the dial tone is detected.

When the handset is lifted from the external telephone, current also flows through the line and the pho- tocoupler is turned ON/OFF, then the off-hook state is detected.

Signal Name	Type	Active		Description	Destination

REVA1	I	-	Line 1	Current Detection Signal	IC23

REVB1	I	-	Line 1	Reverse Current Detection Signal	IC23

GD-1220/1221	© 2006 - 2008 TOSHIBA TEC CORPORATION All rights reserved
ELECTRICAL CIRCUITS

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Image 68

Toshiba GD-1221, GD-1220 service manual Line current detection circuit, REVA1, Line Current Detection Signal IC23, REVB1

Contents

GD-1220/1221 Page Transportation/Installation Important Service Parts for Safety VorsichtContents 2006 2008 Toshiba TEC Corporation All rights reserved FAX Options GD-1220 GD-1221 RemarksSTUDIO165/205 Available STUDIO167/207/237 System firmware versionSpecifications DBm to -8 dBm The setting can be changed by 1 dB Transmission systemEmbedded DBm to 0 dBm Level -55 dBm or lower cannot be detectedComp Dimension width x length Printing areaFolio Features Specifications and Outline of System 08/08 Accessory Qty Accessories and PartsFollowing accessories and parts come with the FAX unit Option Function Model Extends the FAX functions when the FAX unit is installedOptions ADF Radf System ListNA/EU/AU/TW Units and Components Symbol Name Function Layout of PC BoardsFAX PWA-F-NCU-631LSU-RELATED Functions Recording paper sizeEffective recording area Size Horizontal x Vertical Effective recording areaFor MJD, AUD, ASD, SAD, TWD, and CND models Unit mm inch Inch Feed direction Mm 0.16 inch Effective recording areaSize Horizontal x Vertical Effective recording range 297 x 293 x A4-R 210 x 206 x A5-R 148 x 144 x 257 x 253 xPrint mode Print algorithm Recording paper selection algorithm and print algorithmRecording paper selection algorithm Reception print flowchart Start Receive FAX Judgment parameterDiscard printing Bit Discard parameterVertical reduction print Similar reduction print RTI For MJD, AUD, ASD, SAD, TWD, CND models ScanningST-R Comp Scanning widthRecording paper range A4-R For MJD, AUD, ASD, SAD, TWD, and CND modelsRecording paper range Recording paper range LT long Comp long LD long Comp *2 Comp *1Recording paper range A4 long B4 long A3 long Folio Folio *1Error processing Limitations on reception print Order DrawerLSU-RELATED Functions Circuit Connection and Procedure to Change Mode Dial call-up transmission to a telephone circuitYES Standby stateSelection of the communication mode Procedure to select the transmission modeCommunication mode Toshiba original procedure Telephone circuitSignaling System Diagram and Signal Forms Circuit control signalsThis signal can be sent manually Signal form Signal name Signal formCommunication with the binary signals Image signalMode change is possible only for the original set manually ReceiverOnly error frame retransmitted 1 completed 2 completed Frames received Error occurredMCF CED NsfcsidisCFR Binary signals PIP PINPRI-EOM PRI-MPSFormat When this frame is the last frame, X =FCF FIF FCS FCF format of each binary signal Binary signal FormatTCF 9600 bps, 7200 bps4800 bps, 2400 bps 3 V.8/V.34 communication sequence Standard procedure Transmitter Receiver Line closedSignal name Abbreviation Function Remarks Tone signal between Hz and 3,750 Hz in units150 Hz Frequency transmission CapabilityTRN ALTMaintains the synchroniza 7E H Tion Receives an NSF sent fromTransmitter ReceiverImage data Image data are sent. Transmitter Scrambled data frame to beIs completed Encoded image data Turn off Scrambled 1 is sent forShort training Signal PPS-EOPTransmission of one Is completed Informs to disconnect the lineLine closed DIS cannot be recognized DIALING/COMMUNICATION Control DIALING/COMMUNICATION Control DIALING/COMMUNICATION Control DIALING/COMMUNICATION Control FAX Automatic Switching TEL modeFAX mode General functionsDIALING/COMMUNICATION Control Configuration GD-1220/1221Configuration Description of CircuitsEU/AU/AS/C models Line path switching control circuit Signal Name Type Active Description DestinationCML1 ATT3DB1IC5 RLY3, IC3IC3 Line 1 Dial Pulse Generation Signal Q53 Dial pulse generation circuitLine 1 Dial Pulse Generation Signal Line Current Detection Signal IC23 Line Reverse Current Detection Signal IC23Line current detection circuit REVA1Line 1 Current Detection Signal IC23 Current Reverse Line 1 Current Detection IC23 SignalLine 1 CI Detect Signal IC23 CI detection circuitLine 1 CI Detection Signal IC23 Line monitor circuit FAX boardMonitoring signal Ringer/AlarmLine Monitor LOW HighSound volume PC Boards PWA-F-FAX-635 GD-1220PWA-F-FAX-678 GD-1221 PWA-F-NCU-631 NAD, TWD, SAD PWA-F-NCU-631 MJD, AUD, ASD, CND Electrical Circuits Installation Explanation to the UsersInstallation