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Miscellaneous Carrier Systems

Carrier telegraph systems are used as discussed in Chapter 9. In addition to the applications described in the present chapter, carrier telephone systems are used on power lines for supplying telephone service to rural customers,53,54 for operational communication (and other purposes, such as relaying) on power lines,55 and for communication on submarine cables.56

The rural-line carrier telephone system just mentioned is designated type Ml. Although it is designed primarily for operation over rural electric lines as stated, it is also sometimes installed on a pair of telephone line wires to provide an additional talking channel. In such instances frequencies as high as 450,000 cycles are transmitted over ordinary telephone lines.



Last Update: 2011-05-30