RE: Asynch comm

[Chris Bipes <rpg@xxxxxxxxxxxxxxx>]

It is a check digit.  We use it here but I cannot post the code for calculating the XOR check sum.  LRC stands for Longitude Redundancy Check.  Hint, check out the "C" math functions for using XOR and step thru the string.  LRC includes the character immediately following the STX, X'02', up thru and including the ETX, X'03'.  It is placed immediately following the EXT.  It is best to translate your string to ASCII prior to adding the STX,ETX,LRC.

 

EB:AS   XLATE  RESP        ASRESP

        EVAL   DATAOUT = STX + %TRIMR(ASRESP) + ETX

        EVAL   LRC = $LCR(DATAOUT)

        EVAL   DATAOUT = %TRIMR(DATAOUT) + LRC

 

 

 

Christopher K. Bipes     mailto:ChrisB@Cross-Check.com
Sr. Programmer/Analyst   mailto:Chris_Bipes@Yahoo.com
CrossCheck, Inc.         http://www.cross-check.com
6119 State Farm Drive    Phone: 707 586-0551 x 1102
Rohnert Park CA  94928 Fax: 707 586-1884

If consistency is the hobgoblin of little minds, only geniuses work here.  Karen Herbelin - Readers Digest 3/2000

-----Original Message-----
From: Jim Franz [mailto:franz400@triad.rr.com]
Sent: Monday, May 29, 2000 11:51 AM
To: MIDRANGE-L@midrange.com
Subject: Asynch comm

I am working on an AS/400 to a credit card authorization network. Unfortunately no previous AS/400 has previously certified to this network. I'm hoping someone else has seen this requirement for async communications. The specs from the other system call for me to add an LRC code at end of packet, "each record must be immediately followed by an LRC character that is computed by using the XOR function on each character of the record. This is a data integrity check." The network person on the other side is not able to really describe what it is. Sounds like some sort of check digit for the whole packet. Any ideas?

Jim Franz