Main Distribution Frame (MDF): This is where the phone system's connections are terminated into either 110 or 66 punch down blocks. Jumper cables are used to connect these terminations to house cabling, the telephone company demarcation point, or to other intermediary distribution frames.
Intermediate Distribution Frame (IDF): This is generally a closet or enclosure in a remote part of the building that feeds back to the MDF via large 25 to 100 pair cables. In the IDF jumpers are run from blocks connected to the feeder cables to blocks connected to house cabling.
Demarc (Demark, Demarcation Point): This is the demarcation between what is the local telephone company's responsibility and what is the building owner's responsibility. Usually this is an enclosure with some sort of terminating block inside of it.
Local Exchange Carrier (LEC): This is the local telephone company that delivers the physical PTSN to the building demarc. Alternatively in some areas there are Competitive LECs (CLEC) that provide services over the LEC's cabling.
Foreign eXchange Office (FXO): This is the type of port that usually is connected to PTSN coming from the phone company. It doesn't provide its own power or ground.
Foreign eXchange Station (FXS): This type of port is generally found on PBXs and analog adapters for VoIP systems to "power" analog devices like fax machines and analog phones. It provides ring and supervisory voltage to the line.
|66 blade on left, 110 blade on right|
Spudger (aka Spludger, Pick): This tool is used to remove or adjust jumper cables in cabling blocks. It is very useful to pick out small bits of wire left behind after removing a termination.