AT&T Long Lines almost went digital in 1947?
- The Nov. 1947 Bell Laboratories Record contains an article titled "A Preview
of Radio Relaying", describing the experimental microwave link between the
Labs locations in Murray Hill, NJ and West St. in New York City. The link
is described as "a sort of 'bread-board' model" for the Boston-NYC system,
which went into service that month.
I'll be posting the entire article, but I wanted to call attention to the
last paragraph because it suggests that AT&T planned to use digital
transmission in its first broadband microwave system:
"Tests intended to evaluate possible methods of transmitting multiplex voice
signals were started this year. To date the most comprehensive tests have
been made with a new type of pulse signaling called pulse code modulation.
For these experiments, the New York terminal was converted to a repeater
station and the Murray Hill equipment connected by coaxial lines to a
skeletonized 96-channel PCM terminal in a laboratory room at Murray Hill.
The New York-Murray Hill system provides a convenient facility for
evaluating these and other possibilities in the transmission of multiplex
voice signals. The results will be directly applicable to the system
between New York and Boston as well as to future systems of the same general