is for her or for some other party on the line. On
such lines, of course, code ringing is used and in most cases the
operator's only way of distinguishing between calls for her and those
for some sub-station parties on the line is by listening to the
rattling noise which the drop armature makes. In the case of the
Monarch drop the adjustable spring tension on the armature is intended
to provide for such an adjustment as will permit the armature to give
a satisfactory buzz in response to the alternating ringing currents,
whether the line be long or short.

[Illustration: Fig. 260. Code Signal Attachment]

The Monarch Company provides in another way for code signaling at the
switchboard. In some cases there is a special attachment, shown in
Fig. 260, by means of which the code signals are repeated on the
night-alarm bell. This is in the nature of a special attachment
placed on the drop, which consists of a light, flat spring attached to
the armature and forming one side of a local circuit. The other side
of the circuit terminates in a fixture which is mounted on the drop
frame and is provided with a screw, having a platinum point forming
the other contact point; this allows of considerable adjustment. At
the point where the screw comes in contact with the spring there is a
platinum rivet. When an operator is not always in attendance, this
code-signaling attachment has some advantages over the drop as a
signal interpreter, in that it permits the code signals to be heard
from a distance. Of course, the addition of spring contacts to the
drop armature tends to complicate the structure and perhaps to cut
down the sensitiveness of the drop, which are offsetting
disadvantages.

[Illustration: Fig. 261. Combined Drop and Ringer]

For really long lines, this code signaling by means of the drop is
best provided for by employing a combined drop and ringer, although in
this case whatever advantages are secured by the mechanical
restoration of the shutter upon plugging in are lost. Such a device as
manufactured by the Dean Electric Company is shown in Fig. 261. In
this the ordinary polarized ringer is used, but in addition the tapper
rod carries a latch which, when vibrated by the ringing of the bell,
releases a shutter and causes it to fall, thus giving a visual as well
as an audible signal.

_Electrical_. Coming now to the electrical restoration of drop
shutters, reference is made to Fig. 262, which shows in side section
the