Dr. Spine #44 @3473
Sat Feb 16 12:16:13 1991


                        MINIMUM LINE TESTING REQUIREMENTS

                              AS SET BY THE FCC

             Your local telephone company is required by the FCC to
          provide a minimum level of quality on the lines it maintains
          for your use. Many lines do not meet these standards, and so
          are a source of considerable noise in the transfer of data
          between computers.  A noisy line can make it very difficult
          to upload or download messages and files to a BBS.

             If a sysop complains to the telephone company about line
          noise, there is usually only one option offered: line condi-
          tioning.  This is an extra cost item that they would like to
          sell you.  However, if their line to your computer meets the
          minimum standards, there is no reason you cannot have error
          free transfers at 2400 bps and, if an error correcting proto-
          col is used, reliable operation at 9600 bps is the norm.

             If the telephone company seems reluctant to test your line
          and assure that it meets the minimum requirements (and they
          will), request that they run the following tests and provide
          you with the results.  Let them understand that if they do not
          comply, you will refer the matter to the FCC.  They will NOT
          be happy!

             The following tests should be run:

              1) Frequency sweep.  300 to 3000 Hz

              2) Roll off.  500 - 2500 Hz, with -2 to +8 range,
                 and request 300 - 3000 HZ, -3 to +12 range.
                 1000 Hz tone loss: -16, 1% in either direction

              3) Signal to noise ratio.  24 Db level

              4) White noise C, message Dbrnco

              5) Envelope delay measurement.

              6) Phase jitter.  Not to exceed 10%

              7) Impulse noise test.  Minimum 15 minute count

             Don't worry if you do not understand what all these tests
          mean, the telephone company knows.  These standards are all
          available from the FCC upon request.  When the lines provided
          to you meet these minimums, you will experience reliable,
          accurate, and noise free data transfers.


