DTMF MT8870 Module

I have used XOD a year ago and now playing again.
I’d like to use an MT8870 module to control some relays.

They have 4 binary output pins and a pin for when a tone is present (also a power down and inhibit but no use to me at this stage)

So I’m wondering what is the best way to read the pins to get an addressed output (1 - relay 1, 9-Relay 4)
Do I need to find a way to make it a decimal then if equals 2 then …

or is there a better way?

Thanks
Tony