The Fx 20p cab is a programming lead of sorts but not what you need.
The FX 20p E is a hand held programmer that the fx20p-cab fits into. (The lead also fits beijers HMI's)
The hand held programmer only programs in 'statement list' not ladder. This is probably not the way to go for a beginner (I am presuming you are a beginner)
As stated, the lead you need is called an SC-09. They are not cheap, $100