800 BELL SYSTEM TECHNICAL JOURNAL 



Point-to-point communication facilities are also required for the 

 general administrative business of the airv\^ay and of the air transport 

 companies. 



Along our present airways at short intervals are intermediate 

 landing fields upon which planes may land when forced down by 

 weather or mechanical trouble. Such landings, however, are in- 

 frequent and will presumably become increasingly rare; but when a 

 forced landing does take place instant communication with the nearest 

 airport is urgent on account of passengers, mail, and the air transport 

 company itself. Telephones are now provided at these intermediate 

 fields by the Department of Commerce and kept available for such 

 emergency use. The same telephones can be used, of course, for the 

 routine collection of weather data by the airport meteorologist. 



On some airways communication between terminal landing fields or 

 airports is now handled by radio telegraph and on others by long- 

 distance telephone. Neither system is ideal for the purpose. Radio 

 telegraph is slow and is often unreliable in times of bad static when 

 weather messages become urgent. It also utilizes radio ether channels 

 which are needed for communication with planes. Moreover, a 

 telegraph operator must be constantly listening throughout the 

 twenty-four hours even though messages come infrequentl3^ Com- 

 mercial wire telephone service on the other hand although generally 

 fast and reliable provides no written record of the messages, nor does 

 it economically repeat messages at such other and distant airports as 

 may be interested. Weather conditions at Cleveland, for example, 

 are of interest both to New York and to Chicago airports. Likewise 

 the time of departure of the New York air mail from Chicago is of 

 interest to all landing fields enroute. 



An ideal system which is instantaneous and reliable, repeats messages 

 at all airports, is free from interference, takes up no radio channels, 

 and furnishes a permanent record of all messages at all airports, is the 

 telephone-typewriter service. Telephone-typewriter systems make 

 possible the instantaneous transmission of communications between 

 distant offices and provide simultaneously each office and any desired 

 intermediate stations with typewritten copies. This service has been 

 used for a good many years by the principal press associations and is 

 now being extended rapidly to serve the needs of our larger business 

 organizations. 



To utilize the telephone-typewriter system along an airway requires 

 only the installation of keyboard transmitting apparatus and tape 

 printing apparatus at terminal fields and their interconnection by a 

 private or leased wire circuit. Then anyone familiar with a type- 



