﻿JOURNAL 



OF THE 



ASIATIC SOCIETY 



Part II.— PHYSICAL SCIENCE. 

 No. I.— 1874. 



On the general Theory op Duplex Telegraphy. 

 By Louis Schwendler. 



(Received December, 1873, read 4th February, 1874.) 

 iNTRODUCTIOlSr. 



The name of " Duplex Telegraphy" has been given to that mode of 

 Electric Telegraphy which admits of the simultaneous transmission in 

 opposite directions of signals between two stations through a single wire. 

 That this name is far from happily chosen, is evident ; but, as it is current 

 and has already gained a recognized footing, it is not considered advisable 

 to endeavour to replace it now by a more rational one, and it will therefore 

 be adhered to throughout this paper.* 



In the following investigation I shall endeavour to develop the 

 mathematical theory of " Duplex Telegraphy" in its most general form, 

 with the object of determining not only the best arrangement for any 

 particular method, but also the relative values of different methods. 



It is manifest that having from general considerations decided on the 

 best method, and further determined the best arrangement for this method, 

 the remaining difficulties, due to the nature of the problem itself, will be 

 exhibited in a clearer light, and the means of overcoming them may then 

 be more easily discerned. 



* The German language possesses a peculiarly suitable word iu " Oegensprechen^' aud 

 the idea is fully rendered by " Gleichzeitiges Oegensprechen." 



