What is the full form of MODEM

MODEM: Modulator and Demodulator

Modem stands for modulator and demodulator. It is a network device between the computer system and the telephone line.

The modem consists of two parts which are the modulator and the demodulator. The primary function of the modulator part of any modem is to convert all the digital signals received into analogue signals. The demodulator works just opposite the modulator as it converts all the analogue signals to digital signals.

In simple language, when the sender sends any data, it is in the form of a digital signal; when these digital signals reach the modulator of the modem, the modulator converts those digital signals into an analogue signal. These analogue signals are transmitted to the demodulator through a telephone line, and then the demodulator converts these analogue signals again into digital signals and sends them to the receiver.

Features of Modem

1. Speed

Modem speed is decided or calculated by the rate at which it converts the received digital signals into analogue signals. This rate of conversion or modem speed helps in identifying a better and faster modem for personal or business use accordingly.

The speed of the modem is usually measured in bits per second (bps). However, it can also be calculated in other forms of bps, such as Kbps, Mbps, Gbps, etc.

There are different types of modems, and all of them have different speeds. For example, 2400bps, 56kbps, etc.

2. Self Testing

One of the unique features of a modem is that it can check the analogue and digital connection automatically. It means that when two computers are connected, they are connected using digital signals, and the modem can test it. Similarly, when one modem is connected to another, they are connected in a similar structure over analogue signals, and the modem can test the connection as well.

3. Voice Over Data

The modem also allows voice conversation while transferring the data from sender to receiver. For example, the DSL (digital subscriber line) modem that is used these days allows its users to have telephonic calls while sharing the data, enabling users to use the internet at the same time.

Types of Modem

The types of modems can be divided on the basis of their shape and size. They are usually categorized into the following three types:-

1. External Modem

1. It is an external unit connected to the computer's serial port, such as COM or COM2, by a cable. In other words, the external modem we use is the external part of the computer that we connect to the computer externally through an available communication port, such as COM or COM2, using a wire or cable.
2. External modems are also connected to the telephone through a wall jack. In the modem itself, a jack is a specific port used for the telephone, using which we connect it to the telephone.
3. The external modem is portable, which means we can easily carry the modem from one place to another.
4. The installation of the external modem is much easier as external modems are fitted externally, and there is no need to fit them inside the computer.
5. An external modem is expensive.
6. The modem speed or the data transmission speed of the External Modem is high compared to the internal modem.

2. Internal Modem

1. An internal modem is a circuit board commonly installed in the expansion slots inside the computer's system unit. After the installation, we connect this internal modem through telephone lines.
2. Internal Modems are not portable, so we cannot carry or transfer them from one computer to another easily.
3. Internal Modems are pretty difficult to configure as they need to be installed inside the computer in a specific slot, and that is why they are usually installed by the respective professional technicians.
4. Internal Modems are less expensive compared to External Modems.
5. The drawback of internal modems is that internal modem data transmission speed is slower than the external modem.

3. Wireless Modem

1. Wireless Modem transmits the data signals through the air, which means that no kind of physical media is involved in this kind of modem to transmit the signals.
2. Wireless modems are also known as radio frequency modems because the data which they transmit are in the form of radio waves. Radio waves are such kinds of waves which can be passed through any obstacle.
3. Wireless modems are used with laptops and desktop computers to connect wirelessly to available networks.
4. A specific device is installed in a wireless modem, and it also contains antennas for transmitting signals.