Patent attributes
A plug-in device discrimination circuit is connected to the contacts of a jack. When a plug-in device is plugged into the jack, the circuit discerns the type of device it is, thereby enabling proper interface circuitry to be connected to the plug-in device. The discrimination circuit includes a comparison circuit, a switching network, and a controller. The controller operates the switching network to connect the comparison circuit to the jack contacts. When so connected, the comparison circuit compares the electrical characteristics of at least two of the circuits contained within the plug-in device, and produces an output which varies with the results of the comparison. The controller receives the output of the comparison circuit and may configure additional circuitry to present an appropriate interface to the plug-in device.
