ACK timeout is a critical timing value for long distance links and is often misconfigured. Any links that are further than ~700m requires an ACK timeout adjustment (at both ends of a link).  The ACK timeout value is increased as the link distance increases. The optimal ACK timeout value can be difficult to determine manually therefore Dynamic ACK eases this task quite a bit.

By default, this feature is disabled. To enable it, click the Dynamic ACK checkbox.

When enabled, the Dynamic ACK code uses the current ACK value as a hint, and uses a

converging algorithm, including tx errors etc, to tune up the value to be more precise.

The Inspect for Dynamic Ack value (of e.g. 25 in the screenshot below) means that the Dynamic ACK code will evaluate statistics of the last 25 sent packets. You can choose different number of packets - however, the larger the number, the slower the ACK adjustment will be. When the engine decides that it has converged into an optimum value it will sleep - the number of seconds to sleep is specified in Ack time sleep time.  You can change it to whatever number of seconds you prefer, or works best on a particular link.  The default is 600 seconds or 10 minutes.