The circuit does work without the Extenders. I ensure it was working prior to inserting, but then removed them from the circuit and verified everything was still operational.
The circuit is fairly simple as I am only using 2 End Nodes. The cable length for testing at this point is only 5ft, so relatively small, but the intention is to extend that to roughly 100 ft in the final design.
The circuit leverages a 12V supply (8 – AA batteries) for connecting the Power Extenders, but is run through a 5V Regulator (7805) for powering the chips. The SDA & SCL pins are running into an MCP23017 chip that is being is used to drive other components.
Where I may be missing is the pullup resistors, any guidance that you can provide?