UNC/WN5/FN5/DN5OKIFAX 5700/5900 A3 - 42A3.4 UNC, WN5, FN5 and DN5 Circuit DiagramThe NCU board is selected from UNC, WN5, FN5 and DN5 because it differs depending oncountry’s specifications. Therefore, the NCU circuit diagram is destined for the followingcountries.• UNC circuit diagramUS and Canada.• WN5 circuit diagramSweden, Finland, The Netherlands, Ireland, Portugal, New Zealand, Australia, Belgium,Spain, Greece, Norway, Denmark, Italy, and other countries.• FN5 circuit diagramFrance and UK• DN5 circuit diagramGermany, Switzerland and Austria.1. Block diagram• Figure A3.4.1 shows a block diagram of UNC circuit.• Figure A3.4.2 shows a block diagram of WN5 circuit.• Figure A3.4.3 shows a block diagram of FN5 circuit• Figure A3.4.4 shows a block diagram of DN5 circuit.2. General functions of this circuit are as follows:1) Generates and detects signals to be exchanged with a telephone exchange ornetwork in Phases A and E 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 detection2) Sends various data and signals from the R51 board to the telephone line afteramplification.• Picture data/Protocol/Tonal signals/PB tone, etc.3) Sends the following signals received from the line to the R51 board as dataafter amplification.• Picture data/Protocol/Tonal signals, etc.Note 1: This procedure may be omitted depending on the dial parameters.Note 2: MF (Multi-frequency) tone is generated by the modem and transferredto the telephone line via the NCU board.
