polling

In electronic communication, 'polling' is the continuous checking of other programs or devices by one progam or device to see what state they are in, usually to see whether they are still connected or want to communicate.

Specifically, in multipoint or multidrop communication (a controlling device with multiple devices attached that share the same line), the controlling device sends a message to each device, one at a time, asking each whether it has anything to communicate (in other words, whether it wants to use the line).