The SparkFun differential I2C (PCA9615) breakout board provides an easy interface to allow a ruggedized solution for sending I2C protocol over long cable runs. Terminated with End of Line (EoL) resistance it communicates over a 4 wire differential bus. Each signal SDA and SCL has its own pair of differential signals, the fact it uses differential signalling means its more immune to electrical noise as any error should be cancelled out. This is a wide practice with interfaces such as RS485 or RS422 which is typically used in noisy environments. Two modules can quickly be connected together using any standard strait-through CAT5 patch cable, and you have the option of using the Qwiic interface to connect to your I2C master host processor or I2C slave device, it also has space for a 5 pin, 2.54mm connector, if your not using the Qwiic interface or solder wires direct to the PCB. It requires 5V DC and takes very little current, other I/O is SDA, SCL and there is a chip Enable. The PCA9615 has an internal pullup so the Enable pin can be left floating for normal operation or can be pulled low to disable communications. It has on-board pull up resistors on the SDA and SCL signals, which can be disabled with the cut of two locations on the PCB.