DSL, from the Central Office to the Customer Premise Equipment:

Leaving the Central Office are several cables of several hundred pairs.  They normally are placed in concrete ducts buried underground -- hence the name, "underground cable".  The Underground is also know as the F1 cable.  The cable is actually several pieces of cable, spliced together in manholes.  At some manholes pairs are tapped and run up into a B-Box where they are cross-connected to aerial cables (aka F2 cables.)  Office buildings and larger apartment buildings may have a terminal connected to the F1.  The aerial cable is spliced into aerial terminals where pairs may be tied to a drop wire.  The drop wire drops from the aerial terminal to the protector on the customer's house.
 

Pictuires to come:  Inside a Manhole, The B-Box, Aerial cable, Terminals (aerial and buried), Protectors and NIDs.