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Teletypewriters are widely used for high speed telegraph communications as well as for transmission of written messages. For economical transmission over long distances it is essential that only a single wire or transmission channel be required to carry the signal. Furthermore, the reliable and efficient operation can be secured by using not more than two conditions on the line, such as current and no current, or positive impulses and negative impulses.
Efficient operation can be secured by using more than three conditions on the line.
For business transmission over long distances two transmission channels are used.
Teletypewriters are not used for long speed telegraph communications.
You can transmit written messages with the help of teletypewriters.
