Yes Erik ... there is no RS232

I mention RS232 here because most examples i saw online tie up with Tx and Rx connections of 8051 as the PDF i mention does. Ofcourse Rs232 is different from RS485 but remember RS485 does not define the protocols for data transmissions but Rs232 does .. so in the examples Rs232 is being used as a protocol how the data will be transfered. so i am just clarify this fact.


Michael your suggestion is definately solves the collision problem. Michael let me tell you my application. There is a main panel and there can be remote undefined number of slave units (each with a keypad + LCD + speaker) connected to the main panel. any user on any remote keypad can operate the main system just like he is on the main system which is also monitoring a lot of other activities including keypads. so my only concern is that will this not slow down the main system. will this not be better that a remote unit send a data packet only if a key is pressed on it. any way i think this is the best approach till now untill to avoid collisions until some body else comes in with some thing else



sanjeev please give the web address of the site you mention.



Shahzad