ines, each operator may
reach, for calling purposes, every line which enters that office. It
is probable that the invention and development of the multiple
switchboard was the first great impetus toward the wide-spread use of
telephone service.

Coincident with the development of the multiple switchboard for
manually operated, central-office mechanisms was the beginning of the
development of automatic apparatus under the control of the calling
subscriber for finding and connecting with a called line. It is
interesting to note the general trend of the early development of
automatic apparatus in comparison with the development, to that time,
of manual telephone apparatus.

While the manual apparatus on the one hand attempted to meet its
problem by providing local trunks between the various operators of a
central office, and failing of success in that, finally developed a
means which placed all the lines of a central office within connecting
reach of each operator, automatic telephony, beginning at that point,
failed of success in attempting to bring each line in the central
office within connecting reach of each connecting mechanism.

In other terms, the first automatic switching equipment consisted of a
machine for each line, which machine was so organized as to be able to
find and connect its calling line with any called line of the entire
central-office group. It may be said that an attempt to develop this
plan was the fundamental reason for the repeated failure of automatic
apparatus to solve the problem it attacked. All that the earlier
automatic system did was to prove more or less successfully that
automatic apparatus had a right to exist, and that to demand of the
subscriber that he manipulate from his station a distant machine to
make the connection without human aid was not fallacious. When it had
been recognized that the entire multiple switchboard idea could not be
carried into automatic telephony with success, the first dawn of hope
in that art may be said to have come.

Success in automatic telephony did come by the re-adoption of the
trunking method. As adopted for automatic telephony, the method
contemplates that the calling line shall be extended, link by link,
until it finds itself lengthened and directed so as to be able to
seize the called line in a very much smaller multiple than the total
group of one office of the exchange.

A similar curious reversion has taken place in the development of
te