The best way to manage the outputs is to use the 0x48 command. This command allows you to set the state of all of the outputs.
The cmd1 is 0x48, cmd2 is a byte configured by you. The least significant bit is the first output, the second bit the second output, etc…
So, for the 4O, just worry about the first four bits, 1 being ON, 0 being off.
So, if you are only using the first output, the following command will turn the bit relay on
cmd1: 0x48 cmd2: 0x01
To turn it off,
cmd1: 0x48 cmd2: 0x00
All other relays will be off given the above commands.
You can also use 0x45 to turn the output on (with cmd2 being the output) and 0x46 to turn the output off.
See the EZIO spec: