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 telephone or telephone set.  The receiver will, as a rule, be designated as such, rather than as a telephone.  The term subscriber’s station equipment will refer to the complete equipment at a subscriber’s station, and will include the telephone set, the interior wiring, and the protective devices, together with any other apparatus that may be associated with the telephone line and be located within the subscriber’s premises.

Classification of Sets.  Telephones may be classified under two general headings, magneto telephones and common-battery telephones, according to the character of the systems in which they are adapted to work.

Magneto Telephone. The term magneto telephone, as it was originally employed in telephony, referred to the type of instrument now known as a receiver, particularly when this was used also as a transmitter.  As the use of this instrument as a transmitter has practically ceased, the term magneto telephone has lost its significance as applying to the receiver, and, since many telephones are equipped with magneto generators for calling purposes, the term magneto telephone has, by common consent, come to be used to designate any telephone including, as a part of its equipment, a magneto generator.  Magneto telephones usually, also, include local batteries for furnishing the transmitter with current, and this has led to these telephones being frequently called local battery telephones.  However, a local battery telephone is not necessarily a magneto telephone and vice versa, since sometimes magneto telephones have no local batteries and sometimes local battery telephones have no magnetos.  Nearly all of the telephones which are equipped with magneto generators are, however, also equipped with local batteries for talking purposes, and, therefore, the terms magneto telephone and local battery telephone usually refer to the same thing.

Common-Battery Telephone. Common-battery telephones, on the other hand, are those which have no local battery and no magneto generator, all the current for both talking and signaling being furnished from a common source of current at the central office.