Multi-Tech Systems MT5634SMI V.92 manual +Frq, +Fbadmul, +Fbadlin, Receive Quality Thresholds

Chapter 3 – Fax Class 2 Commands

Receive Quality Thresholds

Class 2.1	+FRQ
Write syntax: +FRQ=<pgl>,<cbl>
Values:	0 to 64h for <pgl>
	0 to FFh for <cbl>
Default:	0,0
	This compound parameter replaces the +BADMUL and +FBADLIN parameters used
	in Class 2. The modem may use it to make the "Copy Quality OK" decision in the
	T.30 flow chart (Figure A.7/T.30). If it is used, the modem shall judge copy quality
	unacceptable if either the percentage of good lines is too low or too many
	consecutive lines contain errors. Bad line counts are reported in the +FPS:<blc>
	response. A value of 0 disables either subparameter for use in copy quality checking.
	The first subparameter, <pgl>, specifies the percentage of good lines (e.g. with
	negotiated number of pixels) required for a page to be considered acceptable. For
	example, if the modem counted bad lines (as reported in the +FPS <blc>
	subparameter) and total line count (as reported in the +FPS<lc> subparameter); the
	percentage of good lines would be computed by the following equation:
	100 × (< lc> – <blc>) / <lc>
	If the resulting value is less than the value in <pgl>, the page is unacceptable.
	The second subparameter, <cbl>, specifies the maximum tolerable number of
	consecutive bad lines. If this value is exceeded for a given page, the modem shall
	consider the page unacceptable.
	If the page is found unacceptable by either criteria, the modem shall report the value
	2 for the +FPS <ppr> subparameter, and store that value into the +FPS parameter.

Class 2	+FBADMUL
Write syntax:	+FBADMUL=<value>
Values:	0–255
Default:	20
	This is one of two Class 2 parameters used to determine “Copy Quality OK” on the
	T.30 flow chart. The number of lines received with a bad pixel count is multiplied by
	this number. If the result exceeds the number of lines in the page, then the error rate
	is too high. A value of 20 corresponds to a 5% error rate.
	A value of 0 implies that error checking is not present or is disabled.

Class 2	+FBADLIN
Write syntax: +FBADLIN=<value>
Valid values:	0–255
Default value:	10
	This is the other Class 2 parameter used to determine “Copy Quality OK.” If the
	number of consecutive lines in normal resolution (98 dpi) mode that have pixel count

errors is equal to or greater than <value>, then the copy quality is unacceptable. If the number of consecutive lines in fine resolution (196 dpi) mode that have pixel count errors is equal to or greater than <value> × 2, then the copy quality is unacceptable. “Copy Quality Not OK” occursif either the error percentage is too high or if too many consecutive lines contain errors. Bad line counts are reported in the +FPTS: response.

A value of 0 implies that error checking is not present or disabled.

Multi-Tech Systems, Inc. SocketModem MT5634SMIxx Reference Guide (S000263C) 84