If you are ABSOLUTLY certain that it is telephone then you can put it together with just about anything temporarly.48 volts D.C.would be the maximum and that is only when it is ringing.Might give you a good tingle. Is the phone touch-tone or dial? Touch-tone might be polarity sensitive.Look for a tracer ridge on each end of the wire.The wire itself is 16awg.
It is 48VDC normally. But when it is ringing it is 90VAC superimposed on the wire.
There is no such thing as a stupid question, but there is such a thing as an ignorant person, with a question, trying to learn.