Hi....Yes, there are several systems on the market today that allow ethernet over coax. The one that I'm familiar with is the EthernetStretch product from nitek. I recently used it on a job and found it relatively easy to install. I chose it for a few reasons. First it required no setup. By that I mean I did not have to install any IP addresses or do any network configurations. That seems to be true with most of the units out there. Although several do require setting up switches and pushing buttons to establish communication, the nitek did not..Also of interest to me was that most of the systems forced POE power onto the coax. This is not in keeping with the IEEE802.3 standard. I am aware of some cameras such as the panasonic outdoor domes which do not like POE power which is non-standard compliant. The model I used for my job was the EL1500C, here is a link to that unit
http://www.nitek.net/products/networkextenders/EL1500C.htm
I only needed to install for cameras over the existing coax and that is why chose the single camera set. They do have some larger systems which actually includes a built-in layer 2 switch. I am not sure if anyone else here on the board tried one of their switches and maybe they can better comment on that product. I hope this is of some help to you. Please let us know how your job works out....
