Shahzad Aslam:
Your system design needs to make the main panel the MASTER. Each remote display/keypad would be a SLAVE. The main panel MASTER protocol would then quiery each slave on a periodic basis to see if there are keystrokes or other things for the SLAVE to report.

To ensure the proper performance perception for the user of the remote user consoles it is necessary to design the MASTER poll sequences to occur fast enough!! That is a job for the system design!!

I can say that if you design it this way you can have a successful system implementation. If you follow the scheme where you let any SLAVE send when they feel like it your system will fail to work reliably in some cases.

Michael Karas