…. transmits data over communication lines such as telephone and cables.

…. uses communication equipment to connect two or more computers and their resources

accepts transmission of data, instructions, or information

connects the sending device to the communications channel.

Communications channel: initiates instruction to transmit data, instructions, or information.

Data transmission specifications: rules and procedures that coordinate the sending and receiving devices.

computer or a specialized communication device

Networks are comprised of at least … end stations, and a medium over which data can be carried.

Guided media

signals propagate in solid media: copper, fiber, coax

propagates between transmitter/receiver pairs

Connects your TV to the cable TV system

Consist of two separate insulated copper wires that twisted together

In Twisted Pair wire pairs are …

high-speed point-to-point transmission (10's-1000's Gbps)

More expensive

100 Mbps, 1 Gbps Ethernet

Glass or plastic fibers carrying light pulses, each pulse a bit

low error rate: repeaters spaced far apart, immune to electromagnetic noise

Signal carried in various "bands" in electromagnetic spectrum

No physical "wire"