the
combined drop-and-jack for this class of work is that it prevents the
operator from forgetting to restore the drops. However, she is not
likely to do this with the night-alarm circuit in operation, since the
buzzer or bell would continue to ring as long as the drop was down.

[Illustration: Fig. 294. Upright Magneto Switchboard]

[Illustration: Fig. 295. Upright Magneto Switchboard--Rear View]

_Upright Type Switchboard._ By far the most common type of magneto
switchboard is the so-called upright type, wherein the drops and
jacks are mounted on the face of upright panels rising from a
horizontal shelf, which shelf contains the plugs, the keys, and any
other apparatus which the operator must manipulate. Front and rear
views of such a switchboard, as manufactured by the Kellogg Company,
are shown in Figs. 294 and 295. This particular board is provided with
fifty combined drops and jacks and, therefore, equipped for fifty
subscribers' lines. The drops and jacks are mounted in strips of five,
and arranged in two panels. The clearing-out drops, of which there are
ten, are arranged at the bottom of the two panels in a single row and
may be seen immediately above the switchboard plugs. There are ten
pairs of cords and plugs with their associated ringing and listening
keys, the plugs being mounted on the rear portion of the shelf,
while the ringing and listening keys are mounted on the hinged portion
of the shelf in front of the plugs.

[Illustration: Fig. 296. Details of Drop, Jack, Plug, and Key
Arrangement]

[Illustration: Fig. 297. Cross-Section of Upright Switchboard]

A better idea of the arrangement of drops, jacks, plugs, and keys may
be had from an illustration of a Dean magneto switchboard shown in
Fig. 296. The clearing-out drops and the arrangement of the plugs and
keys are clearly shown. The portion of the switchboard on which the
plugs are mounted is always immovable, the plugs being provided with
seats through which holes are bored of sufficient size to permit the
switchboard cord to pass beneath the shelf. When one of these plugs is
raised, the cord is pulled up through this hole thus allowing the plug
to be placed in any of the jacks.

The key arrangement shown in this particular cut is instructive. It
will be noticed that the right-hand five pairs of plugs are provided
with ordinary ringing and listening keys, while the left-hand five are
provided with party-line ringing keys and listening keys. Th