Concept in Definition ABC

In the image above we see binary data and below we see data already modulated to send through the telephone line.

A modem is basically a device that modulates and demodulates, hence its name modem (mod = modulator dem = demodulator).

It is used to communicate two computers with each other, it performs the function of exchanging digital data. The problem with conventional telephone lines is that they are systems that are made to transmit non-impulse waves of information or information. computing. The modem converts the digital information into a kind of portable wave through the telephone line cable. It is transported using a certain code or transmission language so that the message can only be received by the computer or Username to which it is intended.

The velocity connection with a modem is slow, if we compare it with the current lines of optical fiber, however, it correctly fulfilled the function of connecting to Internet and be able to enjoy this connection. The speed is measured in baud but it is more correct to say bits (unit of information) per second or "bps".

The ordinary telephone line allows data to be transmitted only at a very slow speed, it is for this reason that the modem not only limits to modulate digital data but also compresses it so that more data can be sent over a line in itself very slow.

A classic modem of a lifetime.

There are Integrated Services Digital Network or ISDN modems, however these depend on the coverage that have our telephone company, since it is necessary that our telephone line is close to a switchboard digital. These networks have the advantage of being able to send more data but above all the possibility of receiving calls and faxes while you were connected to the network.

Normal modems could also receive faxes and even voice calls, although the latter function was perfectly fulfilled by ordinary telephone lines. A modem made a characteristic noise when connecting to the network, this noise is quite similar to when we call someone and receive a fax that this person has left connected. Connecting with a modem required that we disconnect from the ordinary telephone line and therefore no calls could be received while it was working, hence the practice of an ISDN. The reception of faxes via modem was carried out through a program in our computer. If the computer or PC was turned off when the fax was received, the modem has a memory to store the information and download it, when the user turns on his PC and looks through a program, if a fax has arrived while the computer is off.