Roomba, rootooth nothing happens..

[vic7767]

That might work.

[mfortuna]

The problem with that is you will short two drivers together, i.e. TX on the roomba will short out to TX on the sparkfun. That could be harmful to one or both ICs.

[mfortuna]

To be safe you could unsolder the sparkfun RX and TX wires and replace them with a jumper. Then plug it into the SCI port so it is powered from the robot .

[jmep]

Sparkfun RX and TX wires are disconnected and replaced with a small cable between RX and TX, everything that is sent from my terminal loops back and is displayed on my terminal.

[vic7767]

Well, that certainly shows the the connection is good from the PC through the Rootooth. Evidently there is a fault within the SCI cable or component on the circuit board.