What do you mean by dial pulses, Electrical Engineering

Assignment Help:

Q. What do you mean by Dial Pulses?

Dial Pulses: Dial pulsing (many times known as rotary dial pulsing) is the method originally used to transfer digits from a telephone set to local switch. Pulsing digits from a rotary switch began soon after invention of the automatic switching machines. The idea of dial pulsing is quite simple and is depicted in figure. Process begins when telephone set is lifted off hook, completing a path for current through local loop. When switching machine detects off-hook condition, it responds with dial tone. After hearing the dial tone, subscriber begins dial pulsing digits by rotating a mechanical dialling mechanism and then letting it returns to its rest position. As rotary switch returns to its rest position, it outputs a series of dial pulses corresponding to digit dialled.

Whenever a digit is dialled, loop circuit alternately opens (breaks) and closes (makes) a prescribed number of times. Number of switch make/break sequences corresponds to digit dialled (that is the digit 3 produces three switch openings and three switch closers).

Dial pulses take place at 10 make/break cycles per second (which is a period of 100 ms per pulse cycle). For illustration digit 5 corresponds to five make/break cycles lasting a total of 500ms. Switching machine senses and counts the number make/break pairs in sequence.

829_What do you mean by Dial Pulses.png

Break time is nominally 61 ms and make time is nominally 39ms. Digits are separated by idle period of 300 ms called inter digit time. It is important that switching  machine recognize the  inter  digit  time  so  that  it  can  separate  pulses from successive digits. Central office switch incorporates a special timeout circuit to ensure that break part of dialling pulse isn't misinterpreted as phone being returned to its on-hook (idle) condition.


Related Discussions:- What do you mean by dial pulses

Operation of an integrating circuit, Q. What is the principle of operation ...

Q. What is the principle of operation of an integrating circuit? The RC integrator is typically a series RC circuit that uses the capacitor to develop its output. Since voltage

Open-circuit and load characteristics of generator, Q. Open-circuit and loa...

Q. Open-circuit and load characteristics of generator? The open-circuit and load characteristics of a separately excited dc generator, along with its schematic diagram of conne

Calculate the rated load current of machine, A 500 MVA, 33kv, three phase s...

A 500 MVA, 33kv, three phase steam turbine generator has a synchronous reactance of 1.6 p.u. It delivers a rated output at 0.8 power factor lagging. Calculate (a) The synchronou

Mention the desirable properties of fuse materials, Mention the desirable p...

Mention the desirable properties of fuse materials. A fuse material must possess the properties as follows: Low resistivity - It means, thin wires can be used that will of

de1 board, You will design a significant project on the DE1 board. In some...

You will design a significant project on the DE1 board. In some cases you may want to use the breadboard as well - note that all of the pins at the bottom of the breadboard are lab

Describe the process control instructions, Describe the process control ins...

Describe the process control instructions STC - It sets the carry flag & does not affect any other flag  CLC - it resets the carry flag to zero &does not affect any other fl

Dc motor - motor control , DC Motor The motor  which  require dc  supp...

DC Motor The motor  which  require dc  supply to drive them are called DC motors DC motor  consist  two types  of windings. a. Fields Winding b. Armature Winding

Orthogonal frequency division multiplexing, CURRENTLY, orthogonal frequency...

CURRENTLY, orthogonal frequency division multiplexing (OFDM) is emerging as the preferred modulation technique in modern high data rate broadband wireless mobile communication syst

Voice control mobile base, i need help for my final year project, and i wil...

i need help for my final year project, and i will really appreciate if you can assist me as soon as possible

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