Patent ID: 6885978

Claim:
A method for determining whether a DTE or DCE is being connected with an RS232 serial port, where the RS232 interface includes DSR (Data Set Ready) and CTS (Clear to Send), said method comprising the steps of: providing a state machine having first, second, and third states; sampling the DSR and CTS signals only when a device is connected to or disconnected from the RS232 port; if the DSR and CTS are both non-asserted, transitioning to the first state that indicates no device is connected to the RS232 port; if the DSR and CTS are both asserted, transitioning from the first state to a second state indicating that a DCE is connected to the RS232 port; and if the DSR is non-asserted and the CTS is asserted, transitioning from the first state to a third state indicating that a DTE is connected to the RS232 port.