common, and a misuse of the term to say or write T1 service or DS3 service when describing or meaning a T1 or DS3 access or transport facility. Similar to broadcast operations, communications operations take place in physical facilities-the building that houses operational functions. Then there's access facility, cross-connect facility, switching facility, terminal facility, hosting facility. Use of the term continues loosely, but has precise meaning in the community when it's used in the context of a private line facility. A more specific private line facility might have bandwidth characterization added such as seen in the term E1, J1, T1, E3, J3, T3, or the DS designation in front of the word facility. Forward error correction refers to bits or bytes of information added to content that can be used to detect and reverse errors caused in the transport process. For example, terrestrial and satellite wireless (radio) transmission is said to rely on 3/4 or 7/8 FEC, meaning that for every 3 units of payload, add 1 unit or for every 7 units, add 1 unit of specifically coded information to be used to detect and correct errors in transmission. Interface means a connector, or connection point, sometimes also called service handoff or service demarcation. Such a designation is most useful when it carries a reference to a single standard such as G.703, RS-232, DVB-ASI, or IEEE 802.11. 1 BASIC FUNDAMENTALS, DEFINITIONS, AND KEY TERMS Units of Measurement: Hertz (Hz) 1 cps (cycle per second) Kilohertz (kHz) 1000 cps Megahertz (MHz) 1,000,000 cps Gigahertz (GHz) 1,000,000,000 cps Channel Capacity or Payload Size: Kilobits (Kb) 1000 Bits Megabits (Mb) - 1,000,000 Bits Gigabits (Gb) - 1,000,000,000 Bits Cell, File, or Packet Capacity: 8 Bits Octet 8 Bits Kilobyte (KB) 1024 Bytes Megabyte (MB) 1,048,576 Bytes Gigabyte (GB) 1,073,741,824 Bytes 1 Kilobit is usually understood to mean 1000 bits, 1 Mb is 1,000,000 bits, and SO on. But be careful with the bytes term when measuring or calculating bits in a file or time to move the bi