55 lines
2.3 KiB
Plaintext
55 lines
2.3 KiB
Plaintext
Dr. Spine #44 @3473
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Sat Feb 16 12:16:13 1991
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MINIMUM LINE TESTING REQUIREMENTS
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AS SET BY THE FCC
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Your local telephone company is required by the FCC to
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provide a minimum level of quality on the lines it maintains
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for your use. Many lines do not meet these standards, and so
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are a source of considerable noise in the transfer of data
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between computers. A noisy line can make it very difficult
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to upload or download messages and files to a BBS.
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If a sysop complains to the telephone company about line
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noise, there is usually only one option offered: line condi-
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tioning. This is an extra cost item that they would like to
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sell you. However, if their line to your computer meets the
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minimum standards, there is no reason you cannot have error
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free transfers at 2400 bps and, if an error correcting proto-
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col is used, reliable operation at 9600 bps is the norm.
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If the telephone company seems reluctant to test your line
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and assure that it meets the minimum requirements (and they
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will), request that they run the following tests and provide
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you with the results. Let them understand that if they do not
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comply, you will refer the matter to the FCC. They will NOT
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be happy!
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The following tests should be run:
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1) Frequency sweep. 300 to 3000 Hz
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2) Roll off. 500 - 2500 Hz, with -2 to +8 range,
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and request 300 - 3000 HZ, -3 to +12 range.
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1000 Hz tone loss: -16, 1% in either direction
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3) Signal to noise ratio. 24 Db level
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4) White noise C, message Dbrnco
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5) Envelope delay measurement.
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6) Phase jitter. Not to exceed 10%
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7) Impulse noise test. Minimum 15 minute count
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Don't worry if you do not understand what all these tests
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mean, the telephone company knows. These standards are all
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available from the FCC upon request. When the lines provided
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to you meet these minimums, you will experience reliable,
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accurate, and noise free data transfers.
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