polling
- Polling is a method for controlling transmission sequences. This means the sequential polling, for example from node computers, whether a packet is ready for transmission. If the packet is ready for transmission, the task is executed and the message is "heard" by the controller. If no data packet is to be sent from the queried terminal, the controller is also informed. In this way, the devices are polled one after the other until the test processor releases the transmission. In polling, the communication partners are not equal, because only the polling partner can initiate the communication, the addressed partner can at most block it. In automatic polling, the transmission control from the master station is not interrupted by negative acknowledgements from the satellite stations.
- The term polling also exists as an interrupt mechanism of the central processing unit( CPU). In this mode, the central processing unit checks whether a process has ended or is still active and requests an input. The central processing unit supplies the interrupted process with data and reactivates it.
- Polling is used in various radio technologies. For example, in the regular retrieval of location data from motor vehicles and trucks. The central unit or fleet management then uses Automatic Vehicle Location( AVL) to poll the vehicle's GPS data at regular intervals and feed it into fleet management.