"Communications In English for Engineers" — what does it exactly mean?

Solution 1:

Communications means both those things.

I'd guess it means the human variety due to the "In English" since the same protocols and techniques are used in telecommunications in English as in French, Italian, Mandarin, Klingon, Sindarin, etc. (bar some matters around character encoding, and even these days Unicode means we can mostly used the same technology and otherwise we all use the same underlying technology).

Double check with the college. I've heard some amusing anecdotes about course titles that were taken to mean one thing, but actually meant another thing, when both were perfectly valid ways of understanding the English. You may not want part of your academic year to bring you nothing but an anecdote that is amusing to someone else.

Solution 2:

Communications describes a series of exchanges or correspondences.

Communications carried on between authorities and the kidnapper for 3 weeks.

The two countries continued communications on the matter until it was clear negotiations were futile.

Communication may be the general act of communicating

What we have here is a lack of communication.

Communication is a lost art.

or one specific transmission of information.

This is the last communication I'm ever sending to you.

The first communication I received from him was in 1971.

Expanding on this last point, there are cases where context dictates that communications means multiple transmissions of information which are not necessarily part of a single series of exchanges.

The first communications I received from him were in 1971.

Although grammatically correct, IMO this usage is a bit clumsy.

(Apologies for not answering the OP's question directly.)