Modem(Theoritical Explanation)

MODEM

WHAT IS THIS ?

The abbreviation of modem is MODULATOR - DEMODULATOR .It is an electronic device , to a greater extent than oftentimes than non to bear the information betwixt the 2 devices. It has 2 parts namely modulating purpose together with demodulating part, the modulating purpose converts digital information (signals) into analog information (signals) together with the demodulator does the contrary of modulator .

HOW THE CONNECTION IS ESTABLISHED?

1 The sender (DTE) activate the modem (DCE) past times sending some signals(RTS)

t DTE ------------> RTS------------> DC 2 The modem(DCE) at the sending halt post exactly about signals (DCD)to the modem at the receiving end(DCE)

DCE------------->DCD------------>DCE

serial of dot is transmitted betwixt the two modems , until the connecter is established together with this procedure is termed every bit HANDSHAKING

three The modem at the receiving (DCE) halt sends dot (DSR)to the destiny(DTE)

DCE-------------->DSR------------>DTE

iv At final the the receiver(DTE) post the signal(DTR) dorsum to the modem (DCE)from that it goes to exactly about other modem(DCE) together with and thence it(CTS) is directed to the sender(DTE).

{ DTE---->DTR------>DCE } --------------> {DCE------->CTS------>DTE}

RECEIVING END SENDING END

Finally the connecter is established inwards this way . So that the 2 devices are cause to transfer in that place datum.

ABBREVIATION FOR THE TERMS INCLUDED

1. DTE- Data terminal equipment (computer)

2. RTS- Ready to post (signal)

3. DCE- Data communication equipment(modem)

4. DSR- Data laid ready(signal)

5. DTR- Data terminal ready(signal)

6. CTS- Clear to send( signal)

HOW THE DATA IS TRANSMITTED?

First nosotros demand to understand

WHAT IS ANALOG AND DIGITAL SIGNAL ?

ANALOG SIGNAL: Signals which are continuous inwards nature .Since nosotros are surrounded past times the analog signals. Example well ,video , analog clock ,even vocalism of a human also analog . THE WAVE FORM IS SINE .

DIGITAL SIGNAL: They are discreet fourth dimension signals . It is only 0s together with 1s . Example reckoner together with all digital electronics .THE WAVEFORM IS LIKE SQUARE .

Since it has 2 values lone mostly that likewise v (means high voltage/on) together with 0(means ground/off)

MODULATION:

Process of converting digital to analog signal . There are thence many Techniques are available.

1. aAmplitude shift keying(ask)

2. frequency shift keying(fsk)

3. stage shift keying(psk)

4. differential stage shift keying(dpsk).

using whatsoever of the techniques the digital dot from the reckoner tin live on converted to the analog signal.The grouping digital binary information convey for certain make frequency .So the analog equivalence of digital information is exactly a superimpose of grouping of frequency, for to post a massive file nosotros demand to superimpose to a greater extent than frequencies ,but it is express to for certain make inwards a item bandwidth.