Which Of The Following Devices Has More Control Over Which Computers Receive Which Data?

A communications device is any type of hardware capable of transmitting data, instructions, and data between a sending device and a receiving device. 1 type of communications device that connects a communications channel to a sending or receiving device such as a com- puter is a modem. Computers process data as digital signals. Data, instructions, and information travel along a communications channel in either analog or digital form, depending on the com- munications channel. An analog bespeak consists of a continuous electrical wave. A digital bespeak consists of private electrical pulses that correspond bits grouped together into bytes.

For communications channels that use digital signals (such as cable television lines), the modem transfers the digital signals between the calculator and the communications aqueduct. If a communications channel uses analog signals (such as some phone lines), however, the modem offset converts between analog and digital signals.

The following pages describe the following types of communications devices: punch-up modems, ISDN and DSL modems, cable modems, wireless modems, network cards, wireless access points, and routers.

Dial-Up Modems

As previously discussed, a computer's digital signals must exist converted to analog signals before they are transmitted over standard telephone lines. The communications device that performs this conversion is a modem , sometimes chosen a dial-upwardly modem. The give-and-take, modem, is derived from the combination of the words, modulate, to alter into an analog point, and demodulate, to convert an analog signal into a digital signal.

A modem commonly is in the form of an adapter card that yous insert in an expansion slot on a com- puter's motherboard. Ane end of a standard telephone cord attaches to a port on the modem card and the other end plugs into a telephone outlet.

ISDN and DSL Modems

If you access the Internet using ISDN or DSL, you demand a communications device to send and receive the digital ISDN or DSL signals. An ISDN modem sends digital data and information from a computer to an ISDN line and receives digital data and data from an ISDN line. A DSL modem sends digital data and information from a computer to a DSL line and receives digital data and information from a DSL line. ISDN and DSL modems commonly are external devices, in which 1 end connects to the telephone line and the other terminate connects to a port on the system unit.

Cable Modems

A cable modem is a digital modem that sends and receives digital data over the cablevision television (CATV) network (Effigy 8-18). With more 110 one thousand thousand homes wired for cable tv, cable modems provide a faster Internet access alternative to dial-upwardly for the home user and have speeds like to DSL. Cable modems currently tin transmit data at speeds that are much faster than either a dial-up modem or ISDN.

Wireless Modems

Some mobile users have a wireless modem that uses the jail cell phone network to connect to the Net wirelessly from  a notebook computer, a smart phone, or other mobile device (Figure 8-xix). Wireless modems, which have an external or built-in antenna, are bachelor as PC Cards, ExpressCard modules, and flash cards.

Network Cards

A network card is an adapter menu, PC Card, ExpressCard module, USB network adapter, or flash menu that enables a computer or device that does not take networking capability to access a network. The network carte coordinates the manual and receipt of data, instructions, and information to and from the calculator or device containing the network card.

Network cards are available in a diversity of styles (Figure 8-twenty). A network menu for a desktop computer is an adapter card that has a port to which a cable connects. A network bill of fare for mobile computers and devices is in the class of a PC Bill of fare, ExpressCard module, USB network adapter, or a flash card. Network cards that provide wireless data transmission likewise are available. This blazon of card, sometimes called a wireless network menu, oftentimes has an antenna.

A network menu follows the guidelines of a particular network communications standard, such equally Ethernet or token ring. An Ethernet bill of fare is the nearly mutual type of network bill of fare.

Wireless Access Points

A wireless access point is a central communications device that allows com- puters and devices to transfer data wirelessly among themselves or to transfer data wire- lessly to a wired network (Figure 8-7 on page 303). Wireless access points take high-quality antennas for optimal signals.

Routers

A router is a communications device that connects multiple computers or other routers together and transmits data to its correct desti- nation on the network. A router can exist used on whatsoever size of network. On the largest scale, routers along the Internet courage forrard data packets to their destination using the fastest available path. For smaller business and home networks, a router allows multiple computers to share a single high-speed Internet connection such as a cable modem or DSL modem (Figure viii-21). These routers connect from 2 to 250 computers.

To forbid unauthorized users from accessing files and computers, many routers are protected by a built-in firewall, called a hardware firewall. Some also have built-in antivirus protection. Today's routers or combination wireless access point/routers are piece of cake to configure and secure against unauthorized access.

Which Of The Following Devices Has More Control Over Which Computers Receive Which Data?,

Source: https://sites.google.com/site/pnutpck11/lesson-6---communication-devices

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