Dave,

You're right, it is a firmware problem. The clock is not stopping but following is happening:

This is the instruction causing problems:
debugin 50,rs485_cont,[WAIT("ST"),rs485string[5],rs485string[4],rs485string[3],rs485string[2],rs485string[1],RS485string[0]]

When a not connected wire is touched to one of the connection, a small spike is generated on the RS485 bus. This what i think that happens than: The Debugin receives 1 bit and is endless waiting for the other bits to come. I've the impression that the timeout only works if a full byte is received.

Is my statement correct? How can this be resolved?

Many thanks !