PM>        The modem derives a value based on the current line
PM>conditions
PM>        and compares its to a table.  This table has high and
PM>low
PM>        "water marks" for each carrier type and rate.  If the
PM>        value is within the marks, the modem stays at the
PM>current
PM>        rate.  If the value is beyond the marks then it
PM>attempts to
PM>        shift up or down to a rate that results in staying
PM>between
PM>        the marks.  The value of S191 is used in this
PM>calculation and
PM>        effectively "shifts" the result up or down in
PM>relation to the
PM>        marks.
DH>This is the best explanation of how the modem does this and the
DH>influence of the s191 register that I've heard.  Thanks!
        I'm glad you like it. :-)
        We *TRY* to keep this stuff from being confusing. 
-Patrick Moore
 Sysop of Supra BBS 
CMPQwk1.42 331þWhere does the data written to device NUL go?
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