If your TAC (telephone access controller) module isn't functioning properly, you may need to reset it. To do this, you'll first need to unplug the power cord from the back of the TAC module. Next, remove the cover from the unit and locate the reset button on the circuit board. Press and hold this button for about 10 seconds, then replace the cover and plug the power cord back in. The TAC module should now be reset and working properly.