EXTENSION OF THE TELEPHONE SYSTEM TO SHIPS 



183 



made for General J. J. Carty on February 14, 1921. An earlier 

 demonstration of a similar nature, although not involving Green 

 Harbor, was made for the delegates of the Preliminary International 

 Communications Conference on October 21, 1920. 



Fig. 25 



Conclusions 

 The results of this development may be summed up as follows: 



(1) It has realized a radio- telephone system capable of giving 

 two-way transmission and meeting the requirements imposed 

 by joint radio-wire operation. 



(2) It has demonstrated the actual use of this radio-telephone 

 system in a wire-radio toll circuit as a means for extending the 

 telephone service of the country to include vessels at sea. 



(3) The experiments have demonstrated also the practicability of 

 multi-channel operation from a common land station whereby 

 a number of land subscribers may be connected simultaneously 

 to a number of different vessels. 



(4) The transmission and operating tests show the difficulties 

 attending the establishment and maintenance of the radio- 

 telephone link to a moving vessel and the necessity for careful 



