If you are searching to learn about different types of communication devices with their applications, functions, and examples. Then you just need to read the following description. Let’s read it.
The hardware used to transmit data, instructions, and information between a sending and receiving device is called communication device.
Some important communication devices are as follows:
- ISDN & DSL Modems
- Cable Modem
- Network Interface Card
Modem stands for modulation and demodulation. A modem is a device that switches digital signal into analog and analog signal into digital. Modem forwards and accept data from one computer to another using telephone lines. It is necessary that both the sending and receiving computer must hold modems.
Modulation is a procedure or method of converting the digital signal into analog signal. The computer saves data in digital form. The data is converted from digital to analog form because modem transmits data using telephone line.
Demodulation is a process of converting the analog signal into digital signal. The receiving computer’s modem receives data in analog form. This analog data is then translated back into digital format to be used by the computer.
Features of Modem
Some important features of modem are as follows:
- Speed: The time at which the modem can send data in bps. The speed of modem is normally from 300 bps to 56 kbps.
- Self-Testing: Modem also examines the digital connection with the computer. It also checks analog connection with the remote modem.
- Voice over Data: when data is being transmitted modem also offers the service of a voice conversation. This attribute must exist in both the source and destination modems.
- Error Control: For the purpose to control errors for transmitted data, modems use various techniques.
- Synchronous or Asynchronous Transmission: modems can transmit data in synchronous and asynchronous modes. But normally data is transmitted in asynchronous mode.
Types of Modems
Different types of dial-up modems are as follows:
- External Modem
- Internal Modem
- Wireless Modem
External Modem: it is a stand-alone device that is attached to a serial port such as RS-232 on a computer with a telephone line.
Internal Modem: it is a card inserted into an expansion slot on the motherboard.
Wireless Modem: it is used to access the Web without wire form notebook and handheld computers, cellular phones and other mobile devices.
ISDN & DSL Modems
The modem used with ISDN and DSL are called ISDN and DSL modems. A digital modem sends and receives data and information to and from digital telephone lines like ISDN and DSL. Furthermore, ISDN modem works with ISDN lines and DSL modem works with DSL lines.
Cable Modem is also known as a broadband modem. The cable modem is a stand-alone device connected with a cable to a USB port. It sends and receives data over the cable television network. It provides faster internet speed than dial-up modem and ISDN.
Network Interface Card
Network Interface Card (NIC) is also called LAN adapter. It is used to connect a device to a network. It also used for the management of instructions, transmission of data, and information to and from the computer with NIC.
In addition, NIC works with particular network technology like Ethernet and token ring. The transfer rate of an Ethernet card is from 10 Mbps to 1000 Mbps. Different NICs are available for different types of computers.