el cable multicore es generalmente un cable que tiene varios cables completos por dentro. Al decir cable completo, quiero decir, con su núcleo, blindaje y alambres correspondientes.

I think you are correct: I've never heard of "milticore" cable anywhere before, and it produces only one single hit on Google, which is definitely a typo anyway.

In Spanish, "multicore" cable is most commonly referred to as "multipar", even though this is not always stricly correct from a techincal point of view. In professional audio for example, the thick cable that connects the sound console at the rear of a concert up to all the instruments and mics on the stage is called a "snake cable" in English, but a "multipar" in Spanish.

Strictly speaking, "multipar" should only be used to refer to multi-conductor telephone or network cables that do, in fact, have the individual conductors arranged in pairs.

This does seem to be the case with your translation, as it does refer to "intercommunications" equipment, so it most likely would be technically correct to call it "multipar" here.