Use and Features of Different Types of Communication Devices

A communication device is a physical device that can transmit to another communication device an analog or digital signal over the wire or wirelessly. This can be a user interface such as a telephone, smartphone, or laptop or an intermediary such as a modem, router or switch.

A router is a network hardware that connects networks or subnetworks and is the intermediary between a local area network (LAN) and a wide area network (WAN). It manages traffic by forwarding data packets from the source IP address to the destination IP address(es). This permits more than one device to connect to the same internet to send and receive data. In order to direct data packets to the most efficient path, a router reads a packet’s header and checks against its internal routing table which is a list of paths to various network destinations. Between the source and destination computers are routers and multiple paths of different networks. Some paths may be short but slow while others may be long but fast, depending on how congested the network traffic is. A router’s job is to work out the optimal path by assessing the travel distance and the amount of network traffic. A network administrator can set up a static routing table which pre-determines what routes data packets take. This is common in small networks. In medium to large networks that handle more traffic, dynamic routing is more viable.

A switch is a multi ethernet (RJ-45) port bridge device within a LAN that redirects data packets to its one intended endpoint device by identifying the right media access control (MAC) address. This endpoint device could be another switch, a router or a computer. It works at the data link layer or layer 2 of the open systems interconnection (OSI) model. Computers connect to switches by connecting an ethernet (RJ-45) cable from one computer to one switch port. When one computer pings to another computer, data is sent to the switch which relays the data to all the computers apart from the sending computer, known as flooding. The receiving computers read the packet header to see if their unique MAC addresses match the one in the header, if not, the computers discard the data. Should the MAC addresses match, it replies to the sender computer to form a connection. When a computer first interacts with the switch, the switch creates a content addressable memory (CAM) table that maps computers’ MAC addresses to ports and future data will be transmitted more efficiently instead of broadcasting to all the computers. If the switch is turned off, the CAM table will disappear and have to relearn next time.

A smartphone is an endpoint device used to make phone calls, access the internet, run mobile applications. Smartphones have a touchscreen, though early 3G phones may not. Some smartphones connect to a 3G, 4G or 5G network. As the network upgrades from 3G to 5G, so does the download speed. To support the use of 3G, a 3G SIM card is required. For 4G and 5G, a phone upgrade is required. What makes a phone smart is the ability to connect to the internet and with the help of 4G and 5G, smartphones can stream data constantly such as tracking one’s location. Smartphones have an in-built antenna which constantly sends and receives data packets to and from the nearest cell tower via radio waves for wireless communication.

A laptop is a portable personal computer used for creating word documents, presentations, using design softwares and online activities such as e-commerce, programming, emailing, streaming, watching videos and more. It has a battery, some are detachable, display screen, some are touchscreens, touchpad and memory. It is able to connect to the internet wirelessly or with an ethernet cable.