The big attraction of the SLx is its size. Barely bigger than a Scart plug, the SLx transmitter and receiver units plug directly into the back of the source equipment and the secondary TV, respectively. The transmitter has a Scart adapter that allows it to be swivelled to any angle.
Of course, the power supplies are separate and also on the end of (rather short) cables are the IR 'eye' and emitters (there's three on one cable to cater for an AV 'stack') to connect to the receiver and the transmitter.
In theory, operation is very simple - plug them in, connect up the power supplies and the IR relay gizmos, switch on, select the same frequency from the DIP switches on the sides and off you go.
The problem is that the transmitter is not that powerful and the receiver not all that sensitive, so, hidden away behind the AV equipment and behind the TV, little of the 2.4GHz signal can escape around the home. The SLx had difficult transmitting a picture through a single wall.
Matters can be improved by putting the units on the ends of Scart extension cables but that defeats the whole object.
This is a great shame as the SLx system is capable of superb pictures when the units are close enough to successfully link a signal between them.
If it had more power and was capable of operating better from the units' hiding place, the SLx video sender would be a world-beater. As it is, it's more of an also-ran.