Service Guide OKIFAX 5750/5950Chapter A Board DescriptionsPage: 285A3.4 UNC, WN5, FN5 and DN5 Circuit DiagramThe NCU board is selected from UNC, WN5, FN5 and DN5 because it differs depending on country's specifications. Therefore, the NCU circuit diagram isdestined for the following countries.UNC circuit diagramlUS and Canada.WN5 circuit diagramlSweden, Finland, The Netherlands, Ireland, Portugal, New Zealand, Australia, Belgium, Spain, Greece, Norway, Denmark, Italy, and other countries.FN5 circuit diagramlFrance and UKDN5 circuit diagramlGermany, Switzerland and Austria.1. Block diagramFigure A3.4.1 shows a block diagram of UNC circuit.lFigure A3.4.2 shows a block diagram of WN5 circuit.lFigure A3.4.3 shows a block diagram of FN5 circuit.lFigure A3.4.4 shows a block diagram of DN5 circuit.l2. 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 and E defined by ITU T.30.Loop formation for call originationlLine current detection (see note 1) before call originationlDial tone detection (see note 1)lGeneration of dial pulses (see note 2)lBusy tone detection (see note 1)lRinging signal detectionl2) Sends various data and signals from the R51 board to the telephone line after amplifi-cation.Picture data/Protocol/Tonal signals/PB tone, etc.l
