In this paper we investigate the features of signs in the Sign Languages and the related problems of how to describe the features linguistically. We present a brief overview of the existing Sign notations; the notations allow us to record all Sign elements in the form of a sequence of characters using alphabetic, digital, and various graphic elements. Also, we substantiate our choice of SignWriting system to record Russian Sign Language, where the signs and rules allow us to set the spatio-temporal form of Signs compactly and precisely. Next, we give examples of a Sign Writing using these characters. Finally, we demonstrate the multimedia program «SWiSL», an on-line platform to help people improve their recognition skills in Sign Language writing.