ACK (Acknowledgement Mechanism)
An ACK is the receiver telling the transmitter with a short reply that it decoded the received packet correctly. In one-way transmission the transmitter cannot know whether the command arrived; with an ACK it is proven that the link was genuinely established, and the transmitter can retry if needed or warn the user.
A one-way remote control transmits the packet when the button is pressed and waits without knowing the outcome. If the operator does not see the movement, they cannot tell whether the problem is range, battery or interference. The ACK removes this uncertainty.
- Retry decision: if no ACK arrives, the transmitter resends the same packet; an interference burst is masked this way.
- User feedback: if no ACK can be received, the remote control can indicate with an LED or an audible warning that it is out of range.
- Cost: every ACK requires extra air time and transmitter hardware on the receiver side; consumption increases.
In the XRF protocol used in AXI's HCT400 and HCT402 sets, bidirectional acknowledgement and session verification are among the features listed in the dump data. The practical benefit is that the operator is aware of the link status and is sure the command reached the other side.
Context in which this term is used: Wireless remote control installation: pairing, relay, safety