# Differential I2C setup considerations **URL:** \ **Category:** Qwiic System\ **Tags:** qwiic\ **Created:** [November 14, 2019, 9:25pm UTC](https://community.sparkfun.com/t/differential-i2c-setup-considerations/38224 "2019-11-14T21:25:27Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![bssackma](https://avatars.discourse-cdn.com/v4/letter/b/ed8c4c/32.png) [@bssackma](https://community.sparkfun.com/u/bssackma)\ **Post date:** [November 14, 2019, 9:25pm UTC](https://community.sparkfun.com/t/differential-i2c-setup-considerations/38224/1 "2019-11-14T21:25:27Z")
I have a project where I would like to use a Raspberry Pi with the SparkFun Qwiic HAT ([https://www.sparkfun.com/products/14459](https://www.sparkfun.com/products/14459)) and SparkFun Differential I2C Breakout Boards ([https://www.sparkfun.com/products/14589](https://www.sparkfun.com/products/14589)) to collect basic environmental data at four locations away from the central Pi – each dI2C cable run will be between 25-30’ with the Pi in the middle (kind-of like spokes on a wheel). I am new to dI2C and have a couple questions: - Is it possible to run 4 dI2C lines off of the Pi+Qwiic Hat – any gotchas I should be aware of? - The specs say that the dI2C boards can extend the I2C bus up to 100’ – does this mean that each of my 4 cable runs can be 100’ or am I limited to 100’ across the 4 cable runs, combined? - If I want to plug 2 I2C sensors into the distal ends of each of the 4 cable runs (for a total of 8 sensors), how should I configure the termination resistors on the dI2C breakout boards (i.e., do any of the traces need to be cut and, if so, how do I know which ones)? - I will be using high-quality shielded Cat6 cable (that I’ll terminate myself with shielded connectors) between the dI2C boards coming off the Qwiic HAT - are there any considerations for preparing the Ethernet cables that are used between the pairs of dI2C boards? Thanks for any help; I really appreciate it!