I2C address three lower bits are set

Shorting column 4 adds 4 to the address

Shorting column 2 adds 2 to the address

Shorting column 1 adds 1 to the address

No column shorted: address 0x20

1 and 4 shorted: address 0x25

I2C pull-up selector

In case many units or long cables are connected additional pull-ups might be required on the I2C lines to compensate for the added capacitance.

Add a short/jumper to connect the 4.7 kohm pull-up to the I2C lines.