FUNCTIONAL ARCHITECTURE OF OCB-283 SWITCH

The main functional blocks of a ocb-283 switch are:


• Subscriber access sub system which carries out connection of different
types of analogue and digital subscriber.
• “Connection and control” sub system which carries out connections and
processing of calls including pcm connections.
• Operation and mtce.sub function which does the management of database
and helps in carrying out various maintenance procedures in built in the systems.




BRIEF DESCRIPTION OF THE FUNCTIONAL COMPONENTS:


1. BT(TIME BASE):
Time pulses are generated in triplicate and distributed to lr’s at switching unit.
The time base is usually synchronised with the network by a synch.interface. It
gets the clock from pcms which carry traffic also and synchronises the local clock
with the pcm clock and thus network synchronisation is achieved.


2. HOST SWITCHING MATRIX:
This is a pure switch of maximum 2048 lrs connectivity capability. The switching
of lr time slots are controlled by the function com which in turn obtains the
particulars from call handler known as multiregister.


3. AUXILIARIES:
Auxiliary Equipment Manager
It supports following functions:
-Tone generation
-Frequency generation and reception
-Conference call facility
-Exchange clock


4. CALL HANDLER (MR):
This obtains necessary data from subs.& ckts.&process for connection and
disconnection of call with the help of a database manager tr.
In addition this helps in carrying out ckt.tests and some observations. It
establishes and releases the calls. It takes real time decisions for processing of a
call. The MR also consults TR to find out subscribers entitlements


5. DATA MANAGER(TR):
This is responsible for managing &storing various subscriber and trunks related
database. The data is returned by the call handler as & when required during call
processing.
It also stores routing and analysis data. It converts (or) translates the received
digits into equipment number of the called subscriber.


6. CHARGING FUNCTION (TX):
This function is responsible for charge computation on the basis of certain
charging parameters supplied by the traslator during analysis of digits received
from a source. This also prepares detailed billing messages & forwarding the
same to the operation & maintenance function for further processing .


7. MATRIX HANDLER(GX):
This function is responsible for processing and for defence of connections on
receipt of-
-Request for connection & disconnection from MR or MQ.
-Fault in connection


8. MESSAGE DISTRIBUTION FUNCTION MARKER:
Its function is to format if required & distribute messages. Also supervises
semipermanent links& inter messages between different communication
multiplexes.


9. PCM CONTROLLER(URM):PCM interface receives PCM from other
exchanges remote subs. access units, access networks and digital recorded
announcement systems and the URM function carries out the following—
-hdb3/binary code conversion
-injection/extraction of ts 16 for cas.


10. OM FUNCTION:
This function enables to create all data required for subs/circuits and their testing.
This also enables spontaneously issuing faults & alarm messages in case of
indications coming from OCB units. Also provides features for saving detail
billing/bulk billing messages on magnetic tape. It possess a two way
communication path with the exchange.


11. This is implemented in CSNL/CSBD & is responsible to forward new call
connection & disconnection requests to control functions.