Hi @RichardWilliams
I asked my friend about the System he uses to convert DVB-C to Ethernet, here is what he wrote me:
Basically he uses this device to convert the DVB-C to IP: https://digitaldevices.de/produkte/netzwerk-tv-tuner/octopus-net-c2-4t/
The device has 4 Tuners to feed more than 1 TV oder a TV and 3 streams to record.
It’s a kind of Sat>IP conversion but used with DVB-C: https://de.wikipedia.org/wiki/Sat-over-IP-Technik
On his NAS/Home-Server he runs TVHeadend (http://tvheadend.org/) that’s responsible for channel managment, EPG, recording.
The TV doesn’t connect directly to the Octopus tuner, but to the TVHeadend so that it can use EPG, timeshift, recording and so on.
Connected to the TV he want’s to watch is as PC with Kodi (https://kodi.tv/) with a plugin for TVHeadend.
With this you have the complete comfort and more of a DVB-C TV connected with a IP network.
Important, that all works only with the unencrypted channels in the basic offer of UPC, no CI+ support for a DigiCard.