MODEM

A modem is a device used to modulate and demodulate (amplitude, frequency, phase or other system) signal called a carrier signal input through other modules. Modems have been used since the'60s or before the twentieth century, mainly due to the direct transmission of electronic signals intelligible to long distances is not efficient. For example, to transmit audio signals over the air, would require larger antennas (in the order of hundreds of meters) for proper recepción.Es usually found in many modems switched network response and the ease of automatic dialing, which allowed to connect when receiving a call from the RTC (Switched Telephone Network) and proceed to dial any number previously recorded by the user. Thanks to these functions can be performed automatically all the operations of the establishment of communication