This number belongs to Zoom Technical, a technical recruiting service in MA, so it is not necessarily a crank call. @Tom: It could be a wrong number, or it could be from an old resume in somebody's database.
I get a lot of calls from recruiters, simply because they are lax about checking my availability before calling (I hope that I am not in the position of looking for work for a long time...). I have marked the Call Type as "Unknown" because "legitimate call" was not an option in the drop-down.
A guy called from a "private" number but in our online phone system the number showed as 781-305-8000. The guy asked for one of our Directors of R/D. I asked what he was calling in regards to and he said he had a technical question. I believe he is a technical recruiter so the only "technical" question he had were asking if the Director of R/D was looking for a new job prospect.