What type of voltage does PoE use to power low voltage devices over Ethernet cables?

What type of voltage does PoE use to power low voltage devices over Ethernet cables?

• A. AC voltage
• B. DC voltage
• C. AC and DC voltages
• D. wireless

Answer: (B)

Power over Ethernet sends electrical power along with data, and that power is provided as DC voltage. In PoE, the power sourced from the network equipment is around 48 volts DC, carried over the same Ethernet cable and then converted by the device into the lower voltages it needs. Using DC makes it straightforward to regulate, protect, and step down to the device’s required rails, and it avoids issues that would come with transmitting mains-type AC over a small data cable. The data on Ethernet remains high-frequency AC signals, but the power path itself is DC. So PoE uses DC voltage over Ethernet cables.

Power over Ethernet sends electrical power along with data, and that power is provided as DC voltage. In PoE, the power sourced from the network equipment is around 48 volts DC, carried over the same Ethernet cable and then converted by the device into the lower voltages it needs. Using DC makes it straightforward to regulate, protect, and step down to the device’s required rails, and it avoids issues that would come with transmitting mains-type AC over a small data cable. The data on Ethernet remains high-frequency AC signals, but the power path itself is DC. So PoE uses DC voltage over Ethernet cables.