Here's an ADSL glossary supplied by Art Wagner
DNS
(Domain Name Server) 		Domain Name Servers exist throughout the Internet. Their task is to translate web addresses (www.uswest.net) to their digital equivalent (216.184.234.1) for the purpose of routing traffic through the internet,
Ethernet interface Hardware Address This is a "hardware" address which is unique to each NIC. It is a six group colon (:) separated number reported by the NIC card when it is properly initalized by the system software. It has the form; 00:5A:68:47:DA:80 and is the same under Linux, Windows, MS-DOS, Novell Netware, or any other Operating System.
CO
(Central Office) 		The Qwest telephone switching office which provides connection from a group of telephone subscribers (one or more XXX-0000 to XXX-9999 "exchange groups). In those CO's which are equipped for ADSL a rack, or racks of additional DSL equipment allow "bridging" of the DSL service onto the POTS service of ADSL subscribers as below. 
                    3 point physical wired connection
                                    ^^^
CO switching (dialing) equip>------->|<-------->copper line to your home
ADSL equipment>--------------------->|
DHCP
(Dynamic Host Control Protocol) 		The Cisco 675 can and does do the work of operating the DHCP in a Linux System. The setup within the Linux system sets Linux up as a DHCP Client to the Cisco 675 DHCP Server. In this setup the Cisco provides DHCP leasing services for the Linux system.
FQDN
(Fully Qualified Domain Name) 		The name of a Computer system including its Computer name (as in Apollo) Its network (as in "home" and its domain (as in "sys") If I had a second network for another department (the kids) A computer on that subsystem could be "Richard.kids.sys"
NIC
(Network Interface Card) 		The ethernet card required to connect your computer to the Cisco 675. As far as I know USWest supplies a 3Com 3C905TX 10Mb 10t card as a part of their ADSL install kit.
POS
(Point of Service) 		The point at which the Qwest cable connects to the house wiring.unless you have an in house wiring contract this is the point at which USWest's responsability ends and your's starts.
POTS
(Plain Old Telephone Service) 		Just what it sounds like. Your Telephone service with or without IDSN, DSL, Modem etc. This servise doesn't change (if all goes well and the POTS filters work) they (the filters) prevent the 136Kbps or 340 Kbps suppressed carrier signal from reaching your telephones.
RJ11 The four wire modular connector used to connect a phone, a answering machine, a caller ID display or any other standard telephone device to the telephone line in your home or office. Interconnect cables are available in straight through, used from phone to the wall, and turnover used from the telephone base unit to the handset.
RJ45 Cat5 The eight wire connector used to interconnect ethernet lan devices including NIC cards, Routers, Hubs, and Switches. There are two pairs of wires at the output of each RJ45 device. One is the transmit pair and the other is the receive pair. At the other end of the cable the transmit pair must become the next device's receive pair and the distant device's receive pair is the near device's transmit pair. If two devices are to be connected directly a "turnover" cable which is wired to provide the necessary pair reversal. If a hub or a switch are installed either device provides the pair reversal. Thus if connections are made via a hub device, straight through cables must be used.