Thanks Grumpy_Mike, CrossRoads for the quick response.
My understanding is all the devices should be powered up together using single power source.
We tried to connect 4 devices, one of which will take inputs from the other 3 devices, all 4 connected to a single power source in parallel, powersupply capable of providing enough power(2A, 5V)
Device getting input from other 3 devices was seen to be rebooting randomly.
We will try the 10k resistor method/opto isolator.