Source : Free On-Line Dictionary of Computing

line conditioning
     
         The adjustment of electrical characteristics
        of, e.g., {twisted pair} telephone lines by insertion of
        components such as resistors, capacitors, transformers or
        (commonly) inductors.  Lines intended for analogue voice
        signals usually have inductors inserted every few miles; such
        a line is said to be "loaded".
     
        The special purpose lines which have neither inductors nor the
        DC voltage which powers ordinary telephones are said to be
        "dry," and are much better for data transmission.
     
        (1996-04-07)