The module use the Raspberry Pi Model B through the I2C bus to expand 8 bi-direction IO.
You can operate Pin A0,A1,A2 through the mini jumper to choose the I2C address. You can choose maximum 8 different address from 0x20-0x27.The module lead to the Raspberry Pi’s GPIO again so you can cascade maximum 8 modules one by one

Features:

Input voltage:5V or 3V
8 bi-direction IO
Provide Isolation protection
Communicate with I2C bus
Expand 8 modules maximum
8 different I2C address that you can choose
Reverse insert will not disturb the module
IO definition
The EXT0-EXT7 are 8 bi-direction GPIO that you can use. There are 6 Pins near the letter ” ADDR”. They are Pin A0,A1,A2.You can choose different I2C address through the setup the mini jumper.

Package Included:

1x I2C expansion board