They really are "Pipes"

I wasn't looking for it, but this might be the oldest reference to electronic communication paths as "pipes".  This history page of the top 100 posts of the BBS era has a bunch of examples like that. 

I presume the history of using the word "pipes" in a communication sense comes from the actual use of pipes to talk between two floors in a building or on a ship.  Even as recently as the 40s, talking through pipes was more reliable for short range communication than electric lines.