ADSL. Asymmetrical digital subscriber line, a relatively new method of transmitting data over a single copper telephone line; 8 Mbps download, 1 Mbps upload. Sectors of the industry hope to use ADSL over existing utility phone lines (see POTS) to deliver high-speed Internet service to the home. Check with the local utility, about whether ADSL is available in a particular area and about the connection and service details. Keep in mind that not all ASDL is alike. In the office, the equipment would appear as an ADSL modem at the PC or in a communications closet or room. ADSL equipment would also be located at the phone company central or remote office.
ANSI. American National Standards Institute.
ATM. Asynchronous transfer mode, an emerging technology and a high-speed network that can carry and switch data, real-time voice and real-time video. The data rate is scalable 1.5 Mbps, 25 Mbps, 50 Mbps, 100 Mbps, 155 Mbps, 622 Mbps, pushing towards gigabyte speeds. ATM is a high-end alternative to Gigabit Ethernet. Several emulated ethernet networks can run on a single ATM network. The ATM equipment would appear as rack-mounted gear located in communications closets and rooms. Cabling between ATM gear is typically single- mode and multimode fiber. Cabling to the PC is only as fast as the cable used in other parts of the network. Category 5 (CAT 5) or fiber is typically used.
ATM service is also available from some phone companies, LECs, and their competitors, CLECs. This makes it possible to run an ATM WAN.
Backbone. The cabling that connects the main communications room to the closets.
BICSI. Building Industries Consulting Services International. A telecommunications association that writes standards, provides training, and registers communications designers.
BOCA. Building Officials Code Administrators International, an organization that writes a model building code which has been adopted in whole, or in part, by many jurisdictions.
Bridge. A piece of network gear that connects or bridges between two different types of LAN segments. The equipment would appear as rack-mounted gear located in communications closets usually, but not necessarily, next to the gear of one of the LAN segments it is bridging.
Closet. This is the room where all of the cabling from the telephones and PCs is joined. This room also contains expensive network gear and phone equipment.
There is supposed to be at least one closet per floor, more if the floor is large.
Most people are not allowed in these closets, so they do not understand why so much room is needed, what is in there, or how important the room is. Also the term closet brings to ones mind a 2 ft by 3 ft residential coat closet. This did suffice 50 years ago. Today, a 3-ft clearance is needed on all sides of electronic equipment, so think past a walk-in closet to a large walk-around room.
Cable. An assembly of wires or glass fibers with insulation and jacket; cable can be plenum and non-plenum rated. An outside-plant cable may have waterblocking
gel or tape, metallic or nonmetallic strength members, armoring, and over-jacket.
Carrier. In communications, a continuous frequency that is capable of carrying an imposed signal. The company that provides the continuous frequency.
Category. The Commercial Building Telecommunications Cabling Standard, ANSI/TIA/EIA-568-A defines categories for 100- unshielded twisted-pair cables.
Category 3. This designation applies to cables and hardware up to 16 MHz (16 Mbs).
Category 4. This designation applies to cables and hardware up to 20 MHz (20 Mbs).
Category 5. This designation applies to cables and hardware up to 100-MHz (100 Mbs).
Category 5e. This designation applies to cables and hardware over 100 MHz (over 250 Mbs).
Category 6. This designation applies to cables and hardware over 250 MHz (over 500 Mbs).
Central Office. The office of the carrier where all lines in the local exchange are terminated. The electronic equipment that processes, switches, multiplexes, and interfaces the local exchange traffic with the long-haul system.
Channel. A channel, when referring to horizontal cabling, refers to the cabling from the PC to the communications closet network gear, including all of the patch cables and the patch-panel connectors. (Compare to the definition of a Link.)
Channel Bank. A piece of electronic equipment usually located in the main communications
room that multiplexes or de-multiplexes lines into T1 lines or other high-speed lines.
CLEC. Competitive local exchange carrier. The phone company is a local exchange carrier (LEC). CLECs operate private communications networks that compete with each other and the LEC. CLECs are found primarily in cities.
Cross Connects. In the communications closet, voice lines that come from the main communications room are terminated on blocks. Voice lines that come from wall and system furniture outlets are also terminated on blocks. The interconnecting wiring between the blocks are called cross connects. The term is well suited; cross connects are recognizable at first sight.
CTI. Computer telephone integration; an example of CTI is a PC with telephonesoliciting software and phone headgear so that the operator may use the PC to dial the phone and process data. Databases may be searched automatically and information may pop up (screen pop) on the screen for operator use.
