Baseband ethernet extension system over coaxial cable

An Ethernet extension system, comprising:

• a signal and power conversion device comprising a first signal and power separation unit for receiving integrated baseband network signal and electricity in accordance with Power over Ethernet (PoE) specification, a first signal and power integration unit, a first conversion circuit module connected to and between said first signal and power separation unit and said first signal and power integration unit, and a first coaxial cable interface connected to said first signal and power integration unit, where integrated baseband network signal is separated by said first signal and power separation unit;
• separated baseband network signal is converted by said first conversion circuit module;
• converted baseband network signal is integrated again with separated electricity from said first signal and power separation unit and delivered to said first coaxial cable interface;
• a coaxial cable having a first end connected to said first coaxial cable interface;
• and
• a conversion device comprising a second coaxial cable interface connected to a second end of said coaxial cable, a second signal and power separation unit connected to said second coaxial cable interface, a second conversion circuit module connected to said second signal and power separation unit, and a network interface connected to said second conversion circuit module, where baseband network signal is separated by said second signal and power separation unit, converted by said second conversion circuit module, and delivered to said network interface.