Please note there are two kinds (perhaps more) of switchboard operators. The first worked for the railroad, the second, the one I'm addressing below worked for the telephone service. During the early years of the phone service, there were a lot of legal battles going on about patent problems and such. Something to note for added tension in your historical characters at the time.
Here are some tidbits about a switchboard operator and what their job entailed:
Vhen the capacity of a telephone-exchange system rises above several hundred subscribers the need is felt for labor-saving appliances, chiefly in the work that must be performed by the switchboard operator. This may be divided into several operations, namely, answering calls. calling subscribers, interconnecting subscribers, supervising such interconnections and dissolving the interconnections. However, the limited scope of this article covers only such apparatus as is required for the second or calling operation.
As a rule, the switchboard operator is apprised of a subscriber's desire for a communication by the falling of an annunciator shutter or lighting of a lamp. The signal is then responded to by the operator, either by inserting a plug, pressing a button or other means that may have been provided in the switchboard equipment. Upon learning the subscriber’s needs the operator’s next duty is to learn whether the desired correspondent’s line is free for allowing his signal-receiving apparatus to be sounded. If. on testing or by observation, it is found that the called~for subscriber's line is not already in use the operator’s next duty will be to project a signaling current over the circuit. This brings us to the operation which it is the purpose of this article to describe.
The signaling current for sending out over the line may be (as is the case in the smaller exchange systems) generated by the switchboard operator, while driving an electric generator; however, this operation consumes so much of the switchboard operator's time that it soon becomes a burdensome duty for the operator. In the smaller exchange systems the hand-driven magneto-generator can be em— ployed with good results; in the larger systems, however, where the time consumed while interconnecting the subscribers must necessarily be less, the necessity arises for providing some other means for ringing the subscribers‘ telephone bells; in other words, the electric generator must be driven by some external source of power, such as an electric, gas, water or oil motor. Whichever type of driving engine may be employed, it is essential that its speed should be fairly constant; moreover, its power should be such that even with three or four operators ringing out at the same time its speed shall not be seriously affected. Another important feature provided should be that its internal resistance should be comparatively low, depending, of course, somewhat on the size of the generator armature and field magnets.
Source: Wester Electrician ©1899
In connecting a party line. with a switchboard a great deal of trouble is often caused by the use of an improperly wound annunciator coil. It should be borne in mind that the drop magnet really bears the same relation to the line as the ringer magnets, in the various telephones, and should therefore be connected in the same way. For a series party line the switchboard drop should be wound to about the same resistance as the ringer magnets. If the resistance is made higher, as is often done in' the attempt to secure a more sensitive drop, the parties on the line will have much difficulty in talking to each other, because the drop is in series in the line; but if that line is connected with some other line, through the switchboard, this trouble will not exist, as the circuits should be so arranged as to cut out the drop upon the insertion of the plug.
Source: Electrical Engineering ©1898