Ethernet over servo motor control lines

Hello All. I have two distant locations connected with 3-wire cable - "+", "-" and "common". Voltage 24V DC can occasionally appear between "+" or
"-" and "common". I have to install Ethernet communication through this cable. Modification of special Netgear "Ethernet over Power line" switch solves the problem but I have to disassemble the switch, cut and reconnect some wires. It's too difficult to rebuilt about 200 Netgear switches. Maybe somebody knows the device, which does it 'as is'? Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.