|  | 3.1 | Basic LAN Devices
| 3.1.4 | Media

The symbols for media vary. For example: the Ethernet symbol is typically a straight line with perpendicular lines projecting from it; the token-ring network symbol is a circle with hosts attached to it; and for FDDI, the symbol is two concentric circles with attached devices.

The basic functions of media are to carry a flow of information, in the form of bits and bytes, through a LAN. Other than wireless LANs (that use the atmosphere, or space, as the medium) and the new PANs (personal area networks, that use the human body as a networking medium!), networking media confine network signals to a wire, cable, or fiber. Networking media are considered Layer 1 components of LANs.
You can build computer networks with many different media types. Each media has advantages and disadvantages. What is an advantage for one media (category 5 cost) might be a disadvantage for another (fiber optic cost). Some of the advantages and disadvantages are:

- Cable length
- Cost
- Ease of installation

Coaxial cable, optical fiber, and even free space can carry network signals, however, the principal medium you will study is called Category 5 unshielded twisted-pair cable (CAT 5 UTP).
To find out more about commercially available media, visit:

| Web Links
| Blackbox Network Services
| Micro Warehouse