e impulses, corresponding in number
to the hundreds digit, will energize the vertical relay and cause it, in
turn, to energize the vertical magnet, stepping up the selector shaft to
the level corresponding to the hundred sought. The single rotary
impulse, which follows just before the subscriber's dial reaches its
normal position, will energize the rotary relay of the second selector.
This, in turn, energizes the private magnet which makes a single
movement of its armature and allows the escapement finger on the side
switch arm to move one step and bring the side switch contacts into the
second position.

[Illustration: Fig. 394. Circuits of Second Selector]

_Second Position of Side Switch._ No detailed discussion of this is
necessary, since, with the side switch in its second position, the
actions which occur in causing the wipers of the second selector to seek
and connect with an idle trunk line, are exactly the same as in the case
of the first selector. When the second selector wipers finally reach a
resting place on the bank contacts, the private magnet armature,
operated during the hunting process, is released and the side switch is
thus shifted into the third position.

_Third Position of Side Switch._ The moving of the side switch into its
final position brings about the same state of affairs with respect to
the second selector that already exists with respect to the first
selector. The trunk line is cut straight through and all bridge circuits
or by-paths from it are cut off. The same guarding conditions are
established to prevent other lines or other pieces of apparatus from
making connections that will interfere with the one being established,
and the same provisions are made for working the back release when the
proper impulse comes from the connector, and for passing this back
release impulse on to the first selector in the same way that the first
selector passes it on to the line switch. The line of the calling
subscriber has now been extended to a connector, and that connector is
one of a group--usually ten--which alone has the ability to reach the
particular hundred lines containing the line of the desired subscriber.
The selection has, therefore, been narrowed down from one in ten
thousand to one in one hundred.

=The Connector=--_Its Functions._ It has already been stated that the
connector is of the same general type of apparatus as the first and the
second selectors. Unlike the first and the seco