Onstep ST4 connection

[Luporosso76]

HI,
I read on the onStep wiki that it is possible to connect the ST4 to the board.
The connection requires the use of "2.2K Ohm bussed resistor network 5-pin".
I wanted to know:

1 - Is it necessary even if SHC is not used?
2 - How do you connect the cables of the ST4 cable with the bussed resistor and then everything on the exp1?

Thanks in advance
Alessandro