_1_ and _2_, instead of the
condenser, and these will be charged over the wires _3_ and _4_ from a
source of current at a distant point.

A consideration of the various methods of supplying current from a
common source to a number of lines will show that it is essential that
the resistance of the battery itself be very low. It is also necessary
that the resistance and the impedance of the common leads from the
battery to the point of distribution to the various pairs of lines be
very low, in order that the voice currents which flow through them, by
virtue of the conversations going on in the different pairs of lines,
shall not produce any appreciable alteration in the difference of
potential between the battery terminals.

CHAPTER XIV

THE TELEPHONE SET

We have considered what may be called the elemental parts of a
complete telephone; that is, the receiver, transmitter, hook switch,
battery, generator, call bell, condenser, and the various kinds of
coils which go to make up the apparatus by which one is enabled to
transmit and receive speech and signals. We will now consider the
grouping of these various elements into a complete working
organization known as a telephone.

Before considering the various types it is well to state that the term
telephone is often rather loosely used. We sometimes hear the receiver
proper called a telephone or a hand telephone. Since this was the
original speaking telephone, there is some reason for so calling the
receiver. The modern custom more often applies the term telephone to
the complete organization of talking and signaling apparatus, together
with the associated wiring and cabinet or standard on which it is
mounted. The name telephone set is perhaps to be preferred to the word
telephone, since it tends to avoid misunderstanding as to exactly what
is meant. Frequently, also, the telephone or telephone set is referred
to as a subscriber's station equipment, indicating the equipment that
is to be found at a subscriber's station. This, as applying to a
telephone alone, is not proper, since the subscriber's station
equipment includes more than a telephone. It includes the local wiring
within the premises of the subscriber and also the lightning arrester
and other protective devices, if such exist.

To avoid confusion, therefore, the collection of talking and signaling
apparatus with its wiring and containing cabinet or standard will be
referred to in this work as a tele