This is the worst possible scenario because calls placed in either direction results in the router receiving a call on its' FXO port. In the case of a call that comes in from the PSTN, it might not be as bad. This is because the PSTN switch often provides a disconnect (ground-start or power-denial) and the far-end router ends the call from its' FXO port. However, calls to the PSTN will have the same problems that are discussed throughout this document, because the call comes into the router's FXO port.