What is the behaviour of 997 wait time in X12 integration?

The 997 wait time option in X12 Enveloper Configuration has the following behaviour and properties.

If it is set to 00:00, then it will not wait for the acknowledgement and no entry will be there in the table server.
If it is set to some value,say 00:02 (2 minutes),then it will wait for the acknowledgement for 2 minutes and after that the table entry will get expired and corresponding logs can be seen in the Message Log.