100 line exchange with two-motion line finders, Electrical Engineering

In this design, there are 24 line finders. If any of the 100 subscribers has to get access to any of 24 two-motion selectors, it is necessary that every line finder is capable of reaching any of the 100 subscribers. In other words, every line finder should have 100 outlets. For this purpose, two motion selectors have to be used as line finders. Configuration is displayed in figure. Corresponding outlets of the line finders are commoned. In the same way, outlets of the numerical selectors are also commoned.

When start condition is received, line finder is caused to hunt vertically until wipers reach a marked level. Vertical hunting is then stopped and horizontal hunt commences to find a particular marked contact in that level. It may be noted that in extreme case, line finder may have to take 20-steps -10 vertical and 10 horizontal -before a line is found. Line finders are made to step automatically, using interrupter contact mechanism. When line finder locates the subscriber line, start condition is removed, allotter switch steps on to the next free line finder in readiness for further calls and numerical selector sends out the dial tone to subscriber in readiness to receive dialling pulses. Thereafter establishment of the connection proceeds in usual manner.

Apparently, Design 3 is by far the best for a 100-line exchange. If we had used Uni-selectors as line finders, it would have been essential to divide subscriber's line into small groups of, say 24 each. Such designs involving groupings, functionefficiently only under certain specific traffic conditions and usually result in higher blocking probabilities.

274_100 Line exchange with two-motion line finders.png

Posted Date: 8/23/2013 3:48:43 AM | Location : United States

Related Discussions:- 100 line exchange with two-motion line finders, Assignment Help, Ask Question on 100 line exchange with two-motion line finders, Get Answer, Expert's Help, 100 line exchange with two-motion line finders Discussions

Write discussion on 100 line exchange with two-motion line finders
Your posts are moderated
Related Questions
what is an useful life time in bathtub curve?

A radar systemuses pulses of duration D tomodulate the amplitude of a radio carrierwave. The system can distinguish between targets spaced apart by a distance of d ≥ cD, where c is

Define Serial In - Serial Out Shift Registers? An essential four-bit shift register can be constructed using four D flip-flops. The register is the first cleared forcing all fo

Explain frequency selective wave analyser with bandwidth

Q. Explain about 'Emitter Follower'? EMITTER FOLLOWER : An emitter follower circuit shown in the figure is widely used in AC amplification circuits. The input and output of the

Q. Explain various functions of telephone switching systems. Ans: Functions of telephone switching systems are: (i)  Attending: The system should be continually monito

biography of scientists in different branches

Q. Sketch a typical circuit for a 2-input, 4-output decoder.

The voltage across a 1 - μF capacitor is given. Which is the sinusoidal expression for the current? a) 30 sin200t b) 70cos (800t - 20°) At what frequency will the re

Signals in Noise: Let us now consider a weak information signal that is to be amplified by a noisy amplifier. The signal-to-noise ratio (SNR), usually expressed in decibels, be