his is
likely to be true in large summer resort hotels located in small and
otherwise unimportant rural districts. In one such case within our
knowledge the private branch exchange has a larger number of stations
than the total census population of the town, resulting in an apparent
telephone development considerably greater than one hundred per cent.

_Magneto Type._ Where both the private branch and the main office
equipments are of the magneto type, the private branch requirements are
met by a simple magneto switchboard of the requisite size, and the
trunking conditions are met by ring-down trunks extending to the main
office. In this case the supervision is that of the ordinary
clearing-out drop type, the operators working together as best they may.

_Common-Battery Type._ The cases where the private branch board is of
common-battery type and the main office of magneto type are
comparatively so few that they need not be treated here. Where they do
occur they demand special treatment because the main portion of the
traffic over the trunk lines to the city or town central office is
likely to be toll traffic through that office over long-distance lines.
The principal reason why the equipment of the town offices under such
conditions is magneto rather than common battery is that the traffic
conditions are those of short season and heavy toll, and common-battery
switching equipment at the main office has no especial advantages for
toll work.

[Illustration: Fig. 438. Desk Type, Private Branch Board]

For small private branch exchanges the desk type of switch board, shown
in Fig. 438, is largely used. The operator frequently has other work to
do and the desk is, therefore, a convenience. In larger private
exchanges, such as those requiring more than one operator, some form of
upright cabinet is employed, and if, as sometimes occurs, the branch
exchange is of such size as to demand a multiple board, then the general
form of the board does not differ materially from the standard types of
multiple board employed in regular central office work. The most common
private branch-exchange condition is that of a common-battery branch
working into a common-battery main office. In such the main point to be
considered is that of supervision of trunk-line connections.

_Cord Type._ For the larger sizes of branch exchange switchboards, the
switching apparatus is practically the same as that of ordinary manual
switchboards wherein t