When inputs change on a GPICommander, you will see something like this in the logs:

2023-07-31 13:20:41 Monday GPICommander (10004856): Input 1 status did change to 1
2023-07-02 14:01:43.046372+0200 OnTheAir Video[14156:3335370] GPICommander: Report: ff ff ff ff ff ff ff 

2023-07-31 13:22:29 Monday GPICommander (10004856): Setting Outputs to: f5 
2023-07-31 13:22:29 Monday GPICommander: Report: ff ff ff f5 ff ff ff 

You can see that there is a request that is done, and then a report of the device status. The status received is shown in hexadecimal. So not humanly readable. Here's how to know it...

Examples of values

All inputs and outputs off: ff ff ff ff ff ff ff

Inputs

Input 01: fe ff ff ff ff ff ff
Input 02: fd ff ff ff ff ff ff
Input 03: fb ff ff ff ff ff ff
Input 04: f7 ff ff ff ff ff ff
Input 05: ef ff ff ff ff ff ff
Input 06: df ff ff ff ff ff ff
Input 07: bf ff ff ff ff ff ff
Input 08: 7f ff ff ff ff ff ff
Input 09: ff fe ff ff ff ff ff
Input 10: ff fd ff ff ff ff ff
Input 11: ff fb ff ff ff ff ff
Input 12: ff f7 ff ff ff ff ff
Input 13: ff ef ff ff ff ff ff
Input 14: ff df ff ff ff ff ff
Input 15: ff bf ff ff ff ff ff
Input 16: ff 7f ff ff ff ff ff
Input 17: ff ff fe ff ff ff ff
Input 18: ff ff fd ff ff ff ff
Input 19: ff ff fb ff ff ff ff
Input 20: ff ff f7 ff ff ff ff
Input 21: ff ff ef ff ff ff ff
Input 22: ff ff df ff ff ff ff
Input 23: ff ff bf ff ff ff ff
Input 24: ff ff 7f ff ff ff ff

Outputs

How to interpret it - Using the Calculator app

But you could also have multiple inputs or outputs that turn on at the same time. There can be many configurations that we can not list all here. So the trick is to start the application "Calculator" on your Mac. Select the menu "View > Programmer".

Then make sure to set it to hexadecimal:

Now, make sure to use the important part of the report (the last 3 bytes are unused):

You can then copy and paste these values into the Calculator app, and check which bits are on or off. WARNING:  it's an "inverted" logic as 0 means that the input/output is on, and 1 means it's off.

Inputs

Look for the value of the first 24 bits, there will be 3 groups:

And then in these groups, inputs go from right to left:

If you want to test, you can change the values either in the hexadecimal value, or you can click on the bits and see the hexadecimal value change. In the screenshot below, we have inputs 1 and 9 that are on:

Outputs

As there are only 8 outputs, it's easier, as they are all in one byte:

If you want to test, you can change the values either in the hexadecimal value, or you can click on the bits and see the hexadecimal value change. In the screenshot below, we have outputs 1 and 6 that are on:

Inputs & Outputs

But of course you can combine and use the report with the inputs and outputs at once (but just leave out the 3 last bytes).