I have a GE Fanuc 90 30 PLC and I need to communicate this PLC with an LSI Router. LSI router supports Serial RS 232 communication in binary or ASCII format. I have written a code following GE 0582D Serial Communications manual. I have used COMMREQ instructions to read data at PLC end. Code is successful to read one byte of data only but it fails when greater than one byte is transferred. I need to know how in what sequence should I use COMMREQs? (1. Initialize port, 2. Select Buffer length, 3. Read Bytes/ String, 4. Cancel COMMREQ) If anyone has successfully implemented serial communication RS-232 (Binary / ASCII) for Series 90 30 with a third party device, please share the technique.