Explain the configuration of a step-by-step switching system, Electrical Engineering

Assignment Help:

With neat diagrams explain the configuration of a step-by-step switching system.

Schematic diagram for such an exchange is given in Figure.  Every subscriber is connected to a single rotary pre-selector switch at the exchange, outputs from this switch being connected to a bank of two-motion switches called "group selectors". The  out-puts  from  pre-selector  switches  of  a  whole  group  of subscribers are connected together in parallel as that group of subscribers share a single bank of group selectors. When a subscriber lifts his telephone, cradle switch causes a circuit to be completed back to telephone exchange, signalling that subscriber wishes to make a call. This causes pre-selector switch to step around until it finds a free group selector. Pre-selector switch then stop in this position and group selector is 'seized' by subscriber wishing to make a call.

1747_micro.png

On  seizing  group  selector,  the  subscriber  dials his  first  digit  and  selector switch  moves  up  to  the  appropriate  row  on  switch  contact  array.  Every final selector has the possibility of connection to 100 lines. 1000 lines are thus divided into 10 groups of 100 each, group being identified by the first digit in the subscriber's number. Vertical motion of the group selector hence selects a final selector in the group associated with first digit dialled. Every individual row  of  contacts,  or  levels,  of  group  selector  is  connected  to  a  bank  of  final selectors associated with a specific group of 100line numbers. Having dialled first digit to select appropriate group, group selector arm then automatically rotates  in  vertical  direction  until  it  finds  a  free  final  selector.  In  final selector, both directions of motion are under the control of subscriber's dial and after  dealing  two  further  digits,  connection  is  established,  providing  called subscriber's to answer his telephone.

 

 

 


Related Discussions:- Explain the configuration of a step-by-step switching system

How can a jfet be used as a voltage controlled resistor, Q. How can a JFET ...

Q. How can a JFET be used as a voltage controlled resistor. Explain from drain characteristics? The region to the left of the pinch off locus is referred to as the ohmic region

Improving joints and connections - energy loss, Improving Joints and Connec...

Improving Joints and Connections - Energy Loss Improper joints are a source of energy loss in both overhead and underground systems. The conductivity of joint should not be le

Accelerator and investment, Q. Accelerator and Investment? Accelerator,...

Q. Accelerator and Investment? Accelerator, Investment: Investment spending stimulates economic growth that consecutively stimulates further investment spending (as businesses

Button cells, what is a button cells and how is it used on a low current el...

what is a button cells and how is it used on a low current electronic circuit

Determine the rated stator current, A three-phase, wye-connected, 2300-V, f...

A three-phase, wye-connected, 2300-V, four pole, 1000-kVA, 60-Hz synchronous machine has a synchronous reactanceXs = 5, a field resistance Rf = 10, and an approximately linear ma

Determine sequence of modulation frequencies, The generator of AM EMFs cons...

The generator of AM EMFs consists of a battery-driven radiofrequency (RF) EMF generator connected to a 1.5 m long 50 ? coaxial cable, to the other end of which a stainless-steel sp

Customer indexing scheme, Customer Indexing Scheme: Customer indexing ...

Customer Indexing Scheme: Customer indexing has to be carried out in a way, that makes it probable to associate the customer's geographical and electrical address along with h

Determine the efficiency, Q. (a) Consider a three-phase star or wye half-wa...

Q. (a) Consider a three-phase star or wye half-wave recti?er with a purely resistive load R. Determine: (i) efficiency, (ii) formfactor, (iii) ripple factor, (iv) TUF, and (v) PIV

State the principle of working of transformer, a) State the principle of wo...

a) State the principle of working of transformer. b) A 230/110 V, single-phase transformer takes an input of 350 volt-amperes at no load while working at rated voltage. The core

Detrmine when the current flowing in the conductor, A conductor 300 mm long...

A conductor 300 mm long moves at a uniform speed of 4 m/s at right-angles to a uniform magnetic field of flux density 1.25 T. Verify the current flowing in the conductor when  (

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd