ADDER RC1 Installation And Use Manual page 13

the type B connector (square) plugs into the AdderView. USB cables should be no
longer than 5 metres but this distance may be extended with the use of USB hubs.
You should use tri-coax video cables to achieve a good video picture (the type of
thick cable that you see on computer monitor connections). Lower quality 'data'
cables will function correctly but will generally give relatively poor video pictures and
are only suitable for screen resolutions of 640 x 480. Any unused computer
connections can be left unconnected.
If you are using an Apple Macintosh computer and you wish to use the on/off key
function on the keyboard then you must connect the keyboard directly to the
AdderView's peripheral port A. If you are using this on/off key function then you will
also not be able to use an additional USB hub to extend the cable run between the
computer and the AdderView. This is because the Macintosh on/off key function is
not supported through a USB hub.
AdderView USB Installation and Use Page 12