Microphone Line Based Detection of Headset Plug Removal

A method for operating a telephone device having a headset jack to connect with a headset plug of a headset, the headset having a microphone and a microphone button, the method comprising:

• during a telephone call and with the microphone electrically connected to a signal line of the headset jack, detecting a first signal on the signal line;
• after detecting the first signal, detecting on the signal line a second signal that is different from the first signal;
• determining whether the second signal equals or exceeds a first threshold or equals or is less than a second threshold, wherein the second threshold is less than the first threshold;
• if the second signal equals or is less than the first threshold, maintaining the telephone call.

A method for operating a telephone device having a headset jack to connect with a headset plug of a headset, the headset having a microphone and a microphone button, the method comprising:

• during a telephone call and with the microphone electrically connected to a signal line of the headset jack, detecting a first signal on the signal line;
• after detecting the first signal, detecting on the signal line a second signal that is different from the first signal;
• determining whether the second signal equals or exceeds a first threshold or equals or is less than a second threshold, wherein the first threshold is greater than the second threshold;
• if the second signal is greater than the first threshold, detecting an actuation of the microphone button.

A method for operating a telephony device having a headset jack to connect with a headset plug of a headset, the headset having a microphone and a microphone button, the method comprising:

• during a telephone call and with the microphone electrically connected to a signal line of the headset jack, detecting a first signal on the signal line;
• after detecting the first signal, detecting a second signal on the signal line, wherein the second signal is less than the first signal;
• after detecting the second signal, detecting a third signal on the signal line, wherein the third signal is greater than the first signal;
• and
• maintaining the telephone call based on the detection of the second and third signals.