Rockwell Automation 1771-DB BASIC MODULE - Manual (Page 217)

Chapter
Call Routines 0–68 12
12 -27
Input Argument Five
The fifth input argument should always be 1.
Input Argument Six
The sixth input argument is the string number. If the fourth input argument
does not select internal string usage, the value of this input argument is
ignored, but you must still PUSH the argument.
Input Argument Seven
The seventh input argument is the byte swap selection:
0 = data bytes transferred from the BASIC port are not swapped when
passed to the destination. The data packing order is low byte first, then
high byte per word. The low byte of the first word in the destination file
contains the byte count.
1 = data bytes transferred from the BASIC port are swapped when
passed to the destination. The data packing order is high byte first, then
low byte per word. Swapping does not affect the first word. The low
byte of the first word still contains the byte count.
The last CALL 33 or CALL 34 executed determines the byte swap option
for all active CALL 33 commands previously executed.
Output Argument One
The output argument is the status of the call. It has these values:
0 = successful setup
1 = disabled
2 = bad input parameter
3 = PRT2 is chosen but it is already enabled for DF1 protocol.
Transfer is not executed.
4 = string too small
5 = string is not dimensioned
6 = JW5 not in 16-point position
If data is being received into the serial port faster than the PLC processor is
retrieving data, the input buffer of the port fills up. If you use handshaking
between the port and the external device, no data is lost.