A. B. C.
The A.B.C. Telegraph - the "letter showing telegraph"
Charles Wheatstone, in conjunction with Augustus Stroh, produced an immense number of appliances connected with telegraphy and with acoustics. One of the most important of them was the A.B.C. telegraph, which had a dial with letters around the edge, one of which was indicated at any point of time (essentially a synchronized stop-clock) - the user noted the letter indicated each time the clock stopper. In a later version the transmitter sent multiple pulses which stepped the indicator by the required number of letters.
Introduced about 1860, this telegraph was used for many years in banks and houses of business as well as in private houses until it was replaced after 1878 by the far more convenient telephone.
See Also
Sources of Information
- Pioneers [1]