Network apparatus, method and network for transmitting audio and image information

A method for supplying first and second network devices as subscribers of a network with operating voltage in accordance with a power-over-ethernet protocol, the method comprising the steps of:

• i) providing a power supply,
• ii) providing the first network device,
• iii) providing the second network device, the first network device being connected to the power supply by a first line and to the second network device by a second line,
• iv) transmitting signals, data, and power-over-ethernet operating voltage, in at least the following four layers:
• a) a precision-time-protocol layer,
• b) an ethernet layer,
• c) a data or information layer,
• d) a power-over-ethernet layer, via the line between the power supply and the first network device,
• v) determining a maximum supply input applied to the first network device on the input side of an electrical supply voltage,
• vi) determining the required power input of the first network device,
• vii) determining the power input required for operating the second network device by the first network device by receiving information from the second network device or by retrieving information from the second network device by the first network device,
• viii) comparing the sum of the power intake of the first network device and the power intake of the second the first network device with the supply input provided at the first network device, at the input side.

A network comprising:

• first and second network devices, wherein the first network device is connected to a power supply by a line and data, information, signals and operating voltage are transmitted via the line, using at least the following four layers:
• a) a precision-time-protocol layer,
• b) an ethernet layer,
• c) a data or information layer,
• d) a power-over-ethernet layer,
• wherein the supply of the first network device with operating voltage, by the power supply, is subject to a power-over-ethernet protocol, wherein the first network device is connected to a second network device via a further line, and wherein equipment is arranged on the first network device for carrying out a test as to whether a sufficiently high supply voltage input is applied to the first network device, which voltage input is sufficient for supplying the first network device and the second network device with operating voltage.