"Cash Lane" is just a catch-all term used in the POS industry, though it's used a lot more in Canada and Europe than in the good old U.S. of A.
Without actually looking it up, this cable reminds me of the Communications cable from certain Sharp POS systems. The inter-register communication line is RS-485, and this cable would plug in to the register at the 4P end, then plug into an RJ45 jack at the other end. It is a bit confusing, because it looks like you should be able to just plug it into an ethernet switch, but you can't. If this is, in fact, the cable I'm thinking of, there is an embedded diode so if you accidently plug it into an ethernet port you don't blow up the port on the register.
Anyway, the person probably thought they could buy another register on ePay and hook it up to an existing system. Oops.
