Powered device interface circuit

摘要

A method for communicating multi-bit data from a powered device being powered over communication cabling to power sourcing equipment, the method comprising: exhibiting a signature indicative of a device to be powered over communication cabling; sensing a voltage level indicative of remote powering over communication cabling; prior to connecting power to operational circuitry, transmitting first multi-bit information; subsequently to the transmitting first multi-bit information, connecting power received over the communication cabling to the operational circuitry; receiving information from the operational circuitry; subsequent to receiving the information disconnecting the received power from the operational circuitry; subsequent to the disconnecting, transmitting second multi-bit information associated with the operational circuitry, the second multi-bit information comprising at least one bit being a function of the received information; and re-connecting power received over the communication cabling to the operational circuitry.