She began to paw at her computer keyboard, searching.
Each channel consists of a keyboard and receiver both electrically connected to certain parts of the distributor.
The keyboard has five keys similar to those of a piano, and the letters and figures are obtained by the different combinations which can be formed by the raised and depressed keys.
Each receiver is provided with five electromagnets corresponding to the five keys of the keyboard, and the armatures of the electromagnets can thus repeat the various combinations for all the signals allocated to the different combinations of the keys.
Per forating machines equipped with typewriter keyboards are used for the preparation of the messages, two or three keyboard perforators being employed at each end of the telegraph lines on which the Murray system is used.