Modem and its Types

by worldofitech February 7, 2019, 5:02 am 78 Comments

A modem is a gadget that is used to transmit digital data through an Analog system. The term is determined from”modulator-demodulator”. Modems are sorted based on two criteria:

The first is Data sent/unit time

And the second one is Change in the state of the signal/unit time

The first modem was used during the ’60s decade, to interface over a network of phone lines. It was 1977 when a modem was first used with a computer for transmitting data to another computer. The gadget is used for modulating an Analog transporter signal to carry digital data just as for demodulating a small signal so as for decoding the digital data from the Analog carrier signal. In this article, we will explore the types of modems.

What is the modem?

Modem

Modems are used to transmit digital information via analog systems. The word “Modem” is derived from the term “modulator-demodulator.” The fundamental elements of a modem are to modulate an analog carrier signal to carry digital data and to demodulate a comparable signal in order to disentangle the digital data from the analog carrier signal.

The modem stands for modulator and demodulator.

Modulator means that converts digital signals into analog signals and sends them over telephone lines.

This process is known as modulation.

Demodulator means that the receiving modem converts analog signals into digital signals and this process is known as demodulation.

It helps us to transmit data from one computer to another computer using standard telephone lines.

Transmission Rate:

It includes how many bits per second a modem can transmit or receive.

Speed:

The speed of the modem is determined by the modulation and demodulation standard.

The rate at which a modem converts digital signals into analog signals and sends them over transmission media and modem Converts analog signals into digital signals is called modem speed.

It is measured in bits per second (bps).

Different modems have different speeds

2400 bps, 9600BPS, 56.5KBPS

Self Testing

The modem can test the digital connection with a computer and analog connection with the remote modem.

Voice over Data:

It has the facility of voice conversation while data being is transmitted.

Error Control:

It uses different methods to control errors for transmitting data.

Types of modems

There are many types of modem.

. External Modem

. Internal Modem

. Wireless Modem

Fax modem

Dial-up modem

DSL modem

ISDN modems

Related: Networking

External Modem

An external modem is a removable device which is used for communication purpose. This type of modem is externally connected with a computer with a com port or USB port and has some lights which indicate the processing status. The external modem may dial-up modem or broadband modems.

An external modem is attached to the computer system with the help of COM1 or COM2 ports.

It is connected to the telephone wall jack by another cable.

External power is supplied to it.

It is very easy to setup.

An external modem is an uncounted unit pressed for a situation. Fundamentally, we associate an external modem with the phone line and the computer through cables.

Internal Modem

An internal modem or on-board modem is a type of modem that is installed on the slots of the motherboard. This modem is an expansion card.

An internal modem is a circuit board that can be attached inside the system through expansion slots.

It cannot be moved easily from one pc to another.

It is set up is difficult.

As the name means the inner modems are being associated with the motherboard of our computer. The internal modems are, for the most part, dial-up or wireless (Wi-Fi). The phone network is being used for sending and receiving signals in the event of dial-ups.

Authentication is needed for the connection. In contrast with different modems, dial-up is notably slower. Going to the Wi-Fi modems, there is no compelling reason to interface them with the telephone network, and authentication isn’t needed for such gadgets.

Cable Modems:

The name says everything! We have seen such modems at our homes or at cable administrators’ place. The radio frequency that range that cable TV uses is additionally being used by the cable modems. The using of the existing cable TV foundation that allows the cable TV organizations to give Internet services

Wireless Modem

It is also called a radiofrequency modem.

These are designed to work with cellular technology and wireless local area networks.

These are not yet perfected but the technology is rapidly improving.

Fax modem

The fax modem enables a computer to transmit and receive documents on a telephone line normally called fax. With a fax modem, a computer performs like a fax machine.

Dial-up modem

The dial-up modem transfers the analog signal through ordinary telephone lines. This modem is usually used to connect to isp using analog signals. The dial-up modem may be an external or internal modem.

ADSL Modems:

Asymmetric Digital Subscriber Line or what we call ADSL modems to use phone lines for sending and receiving information. ASDL modems are really quicker than any conventional voiceband modem. The ASDL,as well as Cable modems, are used for providing the broadband web connection. These sorts of modems allow more information to move and that makes the using of the web quicker.

There are two sorts of data transmission used by Modems and those are synchronous and asynchronous. To make it more clear for you timing signals are used for Synchronous transmission and mistake correcting formulas are used for asynchronous transmission. These gadget filter be used for one technique for transmission or the other or can be used for both the ways.

DSL modem

DSL (digital subscriber line) modem also called broadband modem is used for providing broadband service to a different kind of internet connection. These modems transmit height speed data. Broadband modems typically have transfer rates from 1.5 â€” 8 MBPS (megabytes per second), or higher. DSL modems are suitable for high-speed internet and data transfer over an ordinary phone line.

ISDN modem

ISDN stands for integrated services for the digital network is a type of communication standards for simultaneous digital transmission of voice, video data over a single wire or optical fiber. It can operate over a stander telephone, wires, or other media. It is completely digital in nature from one end of the connection to another.