he case of a re-ring, she merely
presses the key that is already down a little way. On the next call if
she is required to press another one of the four keys, the one which
remained down a slight distance on the last call will be released and
the one that is fully depressed will be the one that remains down as
an indication.

Such keys, where the key that was last used leaves an indication to
that effect, are called _indicating_ ringing keys. In other forms the
indication is given by causing the key lever to move a little target
which remains exposed until some other key in the same set is moved.
The key shown in Fig. 266 is an example of this type.

NOTE. The matter of automatic ringing and other special forms of
ringing will be referred to and discussed at their proper places
in this work, but at this point they are not pertinent as they
are not employed in simple switchboards.

Operator's Telephone Equipment. Little need be said concerning the
matter of the operator's talking apparatus, _i.e._, the operator's
transmitter and receiver, since as transmitters and receivers they are
practically the same as those in ordinary use for other purposes. The
watch-case receiver is nearly always employed for operators' purposes
on account of its lightness and compactness. It is used in connection
with a head band so as to be held continually at the operator's ear,
allowing both of her hands to be free.

The transmitter used by operators does not in itself differ from the
transmitters employed by subscribers, but the methods by which it is
supported differ, two general practices being followed. One of these
is to suspend the transmitter by flexible conducting cords so as to be
adjustable in a vertical direction. A good illustration of this is
given in Fig. 270. The other method, and one that is coming into more
and more favor, is to mount the transmitter on a light bracket
suspended by a flexible band from the neck of the operator, a breast
plate being furnished so that the transmitter will rest on her breast
and be at all times within proper position to receive her speech. To
facilitate this, a long curved mouthpiece is commonly employed, as
shown clearly in Fig. 47.

[Illustration: Fig. 270. Operator's Transmitter Suspension]

_Cut-in Jack._ It is common to terminate that portion of the apparatus
which is worn on the operator's person--that is, the receiver only if
the suspended type of transmitter is