2INTRODUCTIONA telephone exchange is a telecommunications system used in the public switched telephone network or in large enterprises.An exchange consists of electronic components and in older system also human operators that interconnect (switch) telephone subscriber lines or virtual circuits of digital systems to establish telephone calls between subscribers.
4MAIN SECTIONS OF EXCHANGE There are three components of exchange:-1.MDF2.Power Plant3.Switching RoomPOWER PLANTMDFSWITCHING ROOM
5MAIN DISTRIBUTION FRAME The Switching Equipment common to all the subscriber of the area is located in an exchangeTo make possible for a subscriber to communicate with remaining subscriber must be connected to the exchangeFrom OCB through PCM connected to various sections like WLL,TAX, etc.
6ORGANISATION OF THE MDF Vertical side Horizontal side > The primary function of MDF is to remove fault. It is also known as Fault Remove Section.> The telephone numbers are also disconnected in the MDF because of some specific reason.ORGANISATION OF THE MDFVertical sideHorizontal side
7VERTICAL SIDERACK: -On the rack, the tags are situated. One rack is having eight tags. The counting is done from up (0) to down (7). TAGS: -Each rack consists of eight tags. 1 tag = 4 core 1 core = 4 bunch 1 bunch = 2 line N.E.:-The word NE stands for the ‘NUMBER OF EQUIPMENT’.It is used for testing number andWEDGE: Wedge is used as a device for checking the ring. Wedge is placed in jack strips, which is connected to telephone for checking.
8HORIZONTAL SIDEThe horizontal side connected to the underground cable.This cable is having 100 pairs. These pair is distributed when we allot the telephone number to the subscriber.Horizontal side is again subdivided in two parts:Another with the subscriber line by using 100 pair underground cable.One part is connected with the vertical side.
9DIFFERENT TYPES OF FAULTS LOOP FAULT:-If two wires are joined together because of improper connection, storming air etc. EARTH FAULT:-If two wires get scrape at some places and if this wire comes in contact with tree, pillar or any metal objects then this type of fault occurs. CABLE FAULT:-For outdoor connections, jelly filled wires are used which are affected by natural causes such as rain, earthquake etc. At such time this fault occurs. DISCONNECT FAULT:-This type of fault occurs due to the breaking of wires between the vertical side & LEN side.
10POWER PLANT T he main parts of the Power Room are:- 1.Batteries 2.UPS(Uninterrupted Power Supply)3.Charging Discharging Unit4.Inverter and Convertor Unit
11OCB-283 EXCHANGEOCB-283(orgando commando B -type 2nd Generation 8300 microprocessor exchange) is digital switching system which supports a variety of communication needs like basic telephony, ISDN, etc.This system has been developed by CIT ALCATEL of France and therefore has many similarities to its predecessor E-10B (also known as OCB-181 in France).
12Connection & Control Units SMC :Main Control StationSMA :Auxiliary Equipment Control StationSMT :Trunk Control StationSMX :Matrix Control StationSTS :Synchronization and Time Base Station
13FEATURES OF OCB-2831.It is a digital switching with single‘T’ stage switch. A maximum of 2048 PCM’s can be connected.2. It supports both analog and digital subscribers.3. It provides telephony, ISDN, Data communication, cellular radio, and other value added services.4.The traffic handling capacity of the system is huge.
14OCB FUNCTIONAL UNIT The OCB283 system is made up of three independent functional units :- "Subscriber Access Subsystem" which carries out connection of analogue and digital subscriber lines.- "Connection and Control" which carries out connections and processing of calls- "Operation and Maintenance" which is responsible for all functions needed by the network operating authority.
15OCB-283 SWITCHING SYSTEMAny Automatic Switching System comprises in general of following distinct Subsystems:-• Subscriber Access SubsystemConnection & Control Subsystem which comprises of(a) Switching Network Units(b) Circuit Connection Units(c) Common Control function units
16GENERAL ARCHITECTURE OF OCB-283 • OCB-283 is the latest Electronics Digital ISDN type Switching technology being imported in INDIA.• THIS IS MANUFACTURED BY M/S ALCATEL OF FRANCE.• This Exchanage works on Stored Programme Control Principle.• Exchange can work with all types of Circuit & Subscriber Signallings & also provides for lot of novel facilities to the subscribers.