he function of this switch is to connect the
conductors of the calling line with the switching devices of the
connective division. Associated with this switch is a register termed
the _decimal register_. The one hundred lines of the section are
terminated in fixed multiple contacts in the cylinder switch of the
primary connector. The calling line is selected and connected with by
adjusting the decimal register to a position corresponding to the
calling line's tens digit and adjusting the brushes of the cylinder
switch to a position corresponding to the calling line's unit digit.

The Rotary Switch:--This is a master switch, or pilot switch,
consisting of a cylinder switch without register. Its duty is the
control of other switches and the completion of circuits formed in part
through other switches. It is the pilot switch and the switch of
initiative and control for the entire connective division.

Signal-Transmitter Controller:--The primary function of this switch is
the generation of signaling impulses of two classes. Impulses of the
first class pass over central-office circuits only and are effective
upon magnets of the divers major and minor switches; impulses of the
second class pass over a line conductor of the calling line and are
effective upon the signal transmitter at the subscriber's station. The
impulses sent out over the line to the subscriber's station cause the
brush to pass over the contacts and thereby indicate the numerical
values of the various digits set by the dials. This switch also enters
in an important manner into the circuits involved in the testing of the
called line for the busy condition. It is controlled by the rotary
switch.

Interconnector Selector:--In an exchange using four digits in the
numbers, the register of the interconnector selector is adjusted in each
call to a position corresponding to the numerical value of the thousands
digit of the called number. The cylinder switch then acts to select an
idle trunk. The switch is controlled by the rotary switch in connection
with the signal transmitter controller.

Interconnector:--This switch is similar to the interconnector selector
in design and in function. It is a cylinder switch with register. The
register is adjusted in each call to a position corresponding to the
numerical value of the hundreds digit of the number called and the
cylinder switch then operates to select an idle trunk. The switch is
controlled by the rotary switch