Oki OF5800 Service Guide - Page 21

Service Manual for OF5800 Chapter 2 Machine Operations Page: 11 The NCU PCB provides the connection to the telephone line. It consists of the interface circuit, dial pulse generator, ring signal detection and telephone control circuit. NCU PCB block diagram Major components of the NCU CML relay - Connects the telephone line to the phone or fax. (CML means Connect Machine to Line) S relay - Used to send dial pulse signals in pulse dialing. OH detector - Detects the On-hook condition of the second telephone unit. H relay - Connects the Tel1 and Tel2 lines to the fax machine. CI Detector - A photo coupler that detects an incoming ring. (CI means Call Indicator) Voltage Circuit - Supplies 24 volts to the relays Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)