I've been lurking at this case for awhile and here are just some of my observations and theories as a person who has been around college/university environments for many years:
1) In many college towns, a few prefixes are known throughout the community as a "university number." For instance, in my town, almost everyone associates the 475- prefix to the University.
2) In the case of the 914- prefix on the note, I think that it is likely one of the "university numbers" which serve the University of North Carolina - Chapel Hill. A University departmental staff manual from the 1998-1999 school year shows that 914-, 962-, and 966- prefixes belong to UNC (
Source).
3) The Carolines' 914- number is likely a UNC campus landline, and I think both they and Jason, are students. The University contracted BellSouth Telecom for its three "University numbers" (
Source).
4) An area code was not listed on the note because it was not needed if one dialed on campus. From the departmental staff manual: "For local, off-campus calls, dial 9 and then the number. For on-campus calls (914, 962 or 966 prefix) dial the last five digits only. The staff phone will not complete long-distance calls. If you need to make a long-distance phone call for business reasons, please see Linda Horne." The university where I work at has a similar dial procedure--last four digits only for a "university number", 9+number for a local call, and approval from a department head for long-distance (you can't dial long-distance from the dorms without using a phone card).
5) Most colleges/university housing departments run a bare-bones operation during the summertime, requiring all students who live on-campus and are taking summer classes to be "consolidated" into one residence hall for economic reasons. Students also have the option of choosing roommates and going back to the same room that they had the prior semester--many schools allow this practice so students can save on storage costs (otherwise they'd have to pack up and take their possessions home or put everything into a Public Storage). This is significant taking into consideration the time of Jason's demise.
So here's my theory:
On June 24 or 25, 1995, Jason met Caroline O. and T., who were dorm roomies, at one of the Grateful Dead shows, where they talked, realized that they all attend UNC-Chapel Hill, and had a super-happy-fun-time together. Since it was the summertime, they had no classes, but the Carolines needed to get back home to family/other summer activity. One of the Carolines gave Jason her dorm number--a known "university number", so they can meet up the following fall semester simply by him dialing the last 5 digits from his residence hall telephone. Unfortunately when fall came, Jason had met his fate, and the two Carolines assumed he dropped out--which many students do after the spring semester--and carried on.
Meanwhile, after the accident which took Jason's life, investigators found the note and could not reach the Carolines because 1) they were not familiar with the Chapel Hill "university number" and could not call it without an area code or 2) they were able to dial the number but being the summertime, the Carolines were not in their dormitory, so the call went unanswered.