Patent ID: 8489781

Claim:
A method of detecting a presence of an externally coupled receiver device, the method comprising: generating a reference current; passing the reference current via a conductor to a shared buffer circuit, wherein the shared buffer circuit is operable to selectively pass the reference current or a communication signal to the externally coupled receiver device; switching between a detect mode where the reference current is provided to the externally coupled receiver device and between a communicate mode where the reference current is blocked and the communication signal is provided to the externally coupled receiver device; monitoring a voltage value of the conductor and a time for the voltage value to reach a pre-determined threshold value in response to the reference current; and detecting a presence of the externally coupled receiver device based on the monitored time, wherein the voltage value rises slower when the externally coupled receiver device is connected and enabled to receive the communication signal than when the externally coupled receiver device is not connected or is not enabled to receive the communication signal.