Increasing Data is needed for some car equipment.
The Idle Message data indicated by Increasing Data Index is increased by Increment every time the Idle Message is sent.

Increment can be -128 ~ 127.
If Increasing Data is not used, set 0 at Increasing Data Index.
You can see the sent Idle Message at Button Property with checking Show how message is sent.
Example:
Idle message is
Dur:200 Len: 2 ID:0500 Data:00 00
Increasing Data Index is 2
Increment is 1.
The data is sent like below every 1 second to car radio though BSGc.

S Len: 2 ID:0500 Data:00 18
S Len: 2 ID:0500 Data:00 19
S Len: 2 ID:0500 Data:00 1A
S Len: 2 ID:0500 Data:00 1B
S Len: 2 ID:0500 Data:00 1C
….