[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 2049 RC232 Q&A Related Knowledge Base Posts -[RC232] Is there an acknowledge message/signal on successful message transmit?[RC232] What the Radiocrafts SoM consist of (inside) ?[RC232] How can I send a pulse from the module?