En9 And Inu Circuit Diagram - Oki OKIFAX4550 Maintenance Manual

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EN9 and INU Circuit Diagram

The NCU board is selected from EN9 and INU because it differs depending on country's specifica-
tions.
• EN9
UK, Flance, EC countries
• INU
US, Canada, Australia, New Zealand, Singapore, China, Malaysia,
non-EC countries (Poland etc.)
1. Block diagram
• Figure A.33 shows a block diagram of EN9 circuit.
• Figure A.34 shows a block diagram of INU circuit.
2. General functions of this circuit are as follows:
1) Generates and detects signals to be exchanged with a telephone exchange or network in
Phases A defined by ITU T.30.
• Loop formation for call origination
• Line current detection (see note 1) before call origination
• Dial tone detection (see note 1)
• Generation of dial pulses (see note 2)
• Busy tone detection (see note 1)
• Ringing signal detection
2) Sends various data and signals from the 46F/R46 board to the telephone line after
amplification.
• Picture data/Protocol/Tonal signals/MF tone, etc.
Note1:
41309401TH Rev.4
This procedure may be omitted depending on the dial parameters.
2: MF (Multi-frequency) tone is generated by the modem and transferred to the
telephone line via the NCU board.
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