2017-10-19 Santa Ana College Early History of Datacomm

From my post to FB group Bell Telephone…

We were having problems with one of our 4 wire point to multipoint datacomm circuits.  Every morning at a little after 9 AM the circuit would go down.  I called in the problem and a Pac Bell tech came out, but couldn’t find a problem.  Next day, same problem – another trouble ticket.  No problem found.  After the third time, the tech said to call it in as a chronic, and gave me his pager #.  Next day, I got him to come out when it was down, and he connected his butt set to see if he could hear some data.  Instead we were hearing a conversation, with someone at a bank!  I guess it was caused by a cable pair that appeared at more than one address (we were using almost all of 53 cable, and part of another cable, too.  We finally got a Lightspan to alleviate the cable overload.)

I think for my first ten years, my pursuing telco trouble tickets and keeping on top of the issues were paying for my salary.  We had dozens of dumb terminals around town all connected to the mainframe computer, when we lost a line, we might have a dozen or more employees sitting with nothing to do.  No wonder we were willing to pay hundreds of dollars a month for those lines.  We started out with a single multidrop line, and a few years later we split it into two lines due mainly to load, and eventually we ended up with four lines, all starting with 74FDDA.  When I came in 1980, the line had been in (and out of) service for probably 6 months but due to outages, those off campus sites were not able to depend on the data entry terminals, instead they just bundled up all the applications and paperwork and sent it over to the college for data entry.  Once I got the problems with the lines straightened out, the offcampus sites started to use the data entry terminals, and became dependent on them, and they put the off campus workers to work doing the data entry.  This, along with our programmers developing more applications, put more load on the whole system.  We had to upgrade the Honeywell Bull mainframes four times during the mainframe years, along with the other infrastructure.  The telephone key systems and switchboard went out and we put in PBX nodes, which still depended on Centrex features form Pac Bell’s Central Office.

This first datacomm line in 1980 was the start of our datacomm metropolitan area network.  We also had dozens of lines on campus that were also multidrop, through telephone cables between bldgs.  That’s how I started out learning about telephones and telecom infrastructure.

Leave a Reply

Your email address will not be published. Required fields are marked *

© RustyBolt.Info/wordpress