44 lines
1.6 KiB
Plaintext
44 lines
1.6 KiB
Plaintext
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AST RESEARCH, INC. TECHNICAL BULLETIN #TB-0339 12/10/87
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AST-5250 ASYNC DIALUP - POSSIBLE CONFIGURATION PROBLEMS
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Here is some additional information that is not contained in
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the file README that comes on the software diskette. (The
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version that this information was obtained from was version
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4.14 of the AST-5250 Async. Dialup).
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The setup for AST modems operating at speeds greater than 2400
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baud includes a command for MNP error correction in reliable
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mode (\N2). MNP error correction has been found to cause
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problems on certain kinds of calls with the AST-5250 Async
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Dialup. Several examples include: Canadian phone lines and
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long-distance calls that use TASI multiplexing. It appears
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that the telephone company equipment is filtering part of the
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signal in these cases. This can lead to communications errors
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such as "Master not communicating with PC" or cause System/3X
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screens to be sent as many as 18 times as reported from a
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Canadian site that examined the signals with a protocol
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analyzer. If these errors occur, it may be necessary to change
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the modem initialization string so that (\N2) becomes (\N1).
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Additionally, problems have been reported with some modems
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timing out before the slave sends its identification. There
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have also been problems reported when customers have used
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hardware flow control with their modems. Hayes and AST modems
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appear to function properly with no errors of these types.
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References:
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----------
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-AT&T Technical Journal
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-AST 2400, 2X2400, 2X9600 modem user's manuals
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-Hayes Smartmodem 2400 user's manual
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