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6. BLOCK DIAGRAM
7. CIRCUIT OPERATIONS
7.1. KEY INPUT CONTROL CIRCUIT
1) Circuit Operation
Sequential input information (negative logic) from the DSHS proprietary telephone is executed
by dynamic scanning.
The ports RR70 to RR73, RR80 to RR83 of IC6 are brought to low status consecutively.
If a key is pressed, the key-in information input is executed by ports R91 to R93, RB1, RB11,
RB21, RB0, RD1.
7.2. LCD CONTROL CIRCUIT
17
Summary of Contents for KX-T7456 - Digital 24 Button Speakerphone Display
Page 4: ...4 DISASSEMBLY INSTRUCTIONS 4 1 HOW TO REMOVE THE LOWER CABINET Procedure 1 4 ...
Page 8: ...5 IC DATA 5 1 IC1 8 ...
Page 11: ...11 ...
Page 15: ...15 ...
Page 20: ...7 4 DATA COMMUNICATION CIRCUIT 1 Function 20 ...
Page 24: ...The reset signal is negledted 24 ...
Page 29: ...8 TROUBLESHOOTING GUIDE 8 1 NO OPERATION 8 2 THE LCD DOES NOT OPERATE 29 ...
Page 31: ...8 5 SPEAKER PHONE TROUBLE 8 6 TONE DIAL TROUBLE 8 7 TROUBLE OF OHCA 31 ...
Page 32: ...8 8 HANDSET TROUBLE 9 TERMINAL GUIDE OF ICS TRANSISTORS AND DIODES 32 ...
Page 36: ...12 CABINET AND ELECTRICAL PARTS LOCATION 13 ACCESSORIES AND PACKING MATERIALS 36 ...
Page 49: ...33 37 34 35 36 25 32 ...
Page 55: ...SW301 CN301 1 2 3 ...
Page 57: ...1 5 2 6 3 7 4 8 ...
Page 58: ...9 13 10 14 11 15 12 16 ...
Page 59: ...17 21 18 22 19 23 20 24 ...