B-c meaning

A4 B C Meridian ci of Greenwich D

At small country towns or villages, where the message traffic is light, the Wheatstone " A B C " instrument is used.

In this apparatus electric A B C currents are generated by turning a handle (placed in front of the instrument), which is geared, in the instru ment.

A noticeable feature in the modern A B C indicator, as well as in all modern forms of telegraph instruments, is the adoption of " induced " magnets in the moving portion of the apparatus.

At offices where the work is heavier than can be dealt with by the A B C apparatus, the " Single Needle " instrument has been very largely employed; it has the advantage of slight Single liability to derangement, and of requiring very little adjustment.