[RC232] I would like to know how to use the pins N°27 and 28 on the RC2500HP Pin 27 and 28 must be left open. Last Update: August 8, 2017 December 20, 2016 1975 RC232 Q&A Related Knowledge Base Posts -[RC232] Is full-duplex scheme feasible with the modules?[RC232] What happens if message buffer of 128 bytes gets completely full?[RC232] Are the modules full duplex ?