[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 2188 RC232 Q&A Related Knowledge Base Posts -[RC232] It is possible to set either4-Byte or 1-Byte addresses in non-volatile memory?[RC232] Can RC232 module be used as a router/range extender device?[RC232] Do you have a FCC ID for the RC2500HP module?