Product data
USRobotics 
Command Reference
Fax Class 1 and Fax Class 1.0 Commands - 120
the received data stream. 
In unframed receive modes, if the modem detects RTC as described in 
Recommendation T.30 prior to initial loss of the high speed carrier, or if the 
modem detects V.21 carrier after initial loss of high speed carrier, then the modem 
immediately accepts the loss-of-carrier as qualified, without waiting for the FCL 
timer to expire. 
In HDLC receive modes, if the modem detects HDLC abort prior to initial loss of 
the high speed carrier, or if the modem detects V.21 carrier after initial loss of high 
speed carrier, then the modem l immediately accepts the loss-of-carrier as 
qualified, without waiting for the FCL timer to expire. 
Write Syntax 
+FCL=<time> 
Defined Values 
<value>  Decimal number representing the loss-of-carrier delay time in 
units of 100 ms. The range is 0 - 255. 
Reporting Current or Selected Values 
Command: +FCL? 
Response: +FCL: <time> 
Example:  +FCS: 0 For the default setting. 
Reporting Supported Range of Parameter Values 
Command: +FCL=? 
Response: +FCL: (<time> range) 
Example: +FCL: (0-255) 
+FDD - Double Escape Character Replacement 
This parameter conditions the use of the ?DLE???SUB? pair to encode 
consecutive <1/0><1/0> in data. This may be used to prevent unbound expansion 
of data that contains many <1/0> patterns. 
Syntax 
+FDD=<value> 
Defined Values 
<value>  Decimal number corresponding to the selected option. For 
modem decode of <DLE><SUB>, the defined range are: 0 
<DLE> <DLE> or discard (default and only) 1 <DLE> <DLE> (not 










