Thre is a CCTV wiring nomenclature that uses UTP cable and associated 4-or-6 position connectors. It is often refered to as RJ11E altough no part I know of is "Registered" with anything. Also, some manufacturers use 4P4C connectors others 6P6C, and yet others 6P4C.
It's a mess.
But, it's a cheap entry-level DIY solution, rapidly being replaced by more standardized (Category-type) cabling and connectors.
I do own a RJ11E system at home. After a bit of tweaking, I managed to have it run over cat5e cable that was already installed. Not sure I would bother with this again, if I had to.
As for the Bosch: their RJ11E uses 4 wires (audio-video-control-power), in 2 pairs, with the pairs wired side-by-side. The RJ11/BNC adapter you linked will NOT work. The proper part name btw, is "balun", as it joins the BA-lanced UTP cable to the UN-balanced coax cable.
