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

Determine voltage and current gain, Q. Determine voltage and current gains ...

Q. Determine voltage and current gains for the CE BJT amplifier shown in Figure with the following parameters: R 1 = 30,000, R 2 = 9000 ,R C = 750 ,R E = 250 , R L = 1000 

What layers are covered under end to end layer connectivity, Q. What layers...

Q. What layers are covered under end to end layer connectivity? Layers 4-7 of ISO-OSI reference model communicate with peer entities in end systems. In intermediate systems,th

Transistor, what is bias compensation

what is bias compensation

State value of current flowing in the winding, The winding of an electromag...

The winding of an electromagnet has an inductance of 3H and a resistance of 15?. When it is connected to a 120 V d.c. supply, Determine: (a)  the steady state value of current f

Computer architecture, outline what three features you would add (choose th...

outline what three features you would add (choose the three that you feel would be most advantageous) to the 16 bit version of the processor in order to enhance its power.

Wien bridge, How i prepare a wien bridge for my college assignemen?

How i prepare a wien bridge for my college assignemen?

Feedback amplifier, Draw and explain the circuit of feedback amplifier

Draw and explain the circuit of feedback amplifier

What are the functional types used in control words of 8251a, What are the ...

What are the functional types used in control words of 8251a? The control words of 8251A are divided into two functional types. 1. Mode Instruction control word 2. Comman

Adc instruction, ADC   Instruction This instruction is used to add th...

ADC   Instruction This instruction is used to add the contents of any register of any register  memory location and carry  flag with the  contents of accumulator  and result  i

Cost and profitability - proposed kpis, Cost and Profitability - Proposed K...

Cost and Profitability - Proposed KPIs  KPI  UOM  Measures   RepresentativeStandards  Aggregate Technical &  Commercial L

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