Page:Popular Science Monthly Volume 88.djvu/403

 Popular Science Monthly

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��translate the Morse code and write out the messages for delivery. The system is entirely practical, and is used in con- nection with the ocean cables. In the United States it is not favored for inter- city telegraphing because of the loss of

��and expense in message handling are saved, and the good features of present- day rapid wire line service are largely due to these installations.

The newest and most perfect page- printing telegraph is that which the \\'estern Electric engineers have recently completed. In this system a single wire is used not only to carry eight messages simultaneously, four in each direction, but to print them on blanks at the receivers, ready for delivery. Thus the speed of direct printing operation (fifty words per minute) is combined with a distribution

���The receiving instru- ment. A telegraph blank is inserted in the instru- ment, and as the perfo- rated tape passes through after receiving its im- pulses over the wire, the message appears in type- written form, ready to be delivered

time which results from the se- ries of processes through which messages must pass.

Automatic telegraphy suggest- A sending operator at the keyboard perforator. This ed l^rinting telegraphy, in which instrument is much Uke a typewriter, but instead ot the mess'i^e received annc'irs in P""ting the letters a group of punches are controlled by tnc message leceuea appears ni ^^^ ^^^^ ^^^ p^^^^j^ ^ ^^p^ ^-^^^ various combmationa

of holes

��typewritten form. The first of these instruments, like the stock- ticker, printed their messages on paper tapes. Soon it became possible to op- erate page-printers over considerable distances by wire. In these a typewriter keyboard transmitter, either directly or through a punched tape, operates over the line a typewriter receiver. The mes- sage is thus printed ready for delivery almost as soon as the transmitting op- erator punches it out on the sounding keyboard. Such printing systems usual- ly o])erate up to fair typewriting speeds of fifty words per minute or so, and can be duplexed. By their use much time

��of one telegraph line among eight pairs of sending and receiving operators. The increases of speed and economy pro- duced by such an arrangement are al- most self-evident.

The apparatus used in this new quad- ruple-duplex system is built up in a group of transmitting, receiving and accessory units. (Ine of the illustrations shows a sending operator at the keyboard per- forator. This instrument is much like a typewriter, but instead of printing the letters a group of punches are controlled by the keys and perforated on a paper

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