Review on Telephone Separator Combiner 3 Female Adapter by Denise Woodcock

Study the wiring diagram carefully and compare it to one of the generally accepted standards. It doesn't suit them, so it's unlikely one could use it to split the four pairs into separate lines in a normal setup. It works as an extension cord if you have four separate devices and one on each end of the cord. But even this is doubtful over a long line, since pairs within cables connected to the standard will be broken and conductors from different pairs will be grouped and possibly twisted together. In a phone system, this can cause crosstalk, but is acceptable over short distances. This would be very unsuitable for high speed data applications.