Data communications over telegraph circuits 1937

CBFalconer

Yes, and also so she would put what she called a "data block" (which I buttume was physically a little solid block of wood or plastic) around the key on that cord position so that it didn't accidentally get bumped before the call was over. When we were finished with the call, we would punch the Voice key on the attached telephone set and flash the hookswitch to get her attention.

(I use the pronoun "she" since nearly all the LD operators back then in the early 70s seemed to be women, although I know that there were a few men operators too).

In this case, the data call was from an IBM 1130 with BSC communications adapter and a big old grey dataphone "breadbox" to a Univac 1108 in a neighboring big city. While it was possible to dial direct, there was IIRC a time limit on directly dialed LD calls which would automatically disconnect after (again IIRC) something like 2 or 3 hours....and many of our online remote batch sessions lasted longer than that. Now that I think about it, there may have also been a Zenith # (this was GTE territory) available for use when placing the call through the operator.

Later on, the powers that be installed a leased conditioned analog private line data ckt for primary use, although there was a little toggle switch which let you use the dialup line as a backup to the PL. Probably that happened when we the dialup usage was extensive enough to justify the economic cost of the private line, not to mention that I believe we could squeeze a little higher speed out of it than the dialup switched path over POTS.