A NEW KF.Y WEST—HAVANA CARRIIiK. TELEPHONE CABLIi 205 



necessary transformers to connect together the parts of the circuit 

 having different impedances. 



The carrier apparatus is installed in existing telephone offices at 

 Key West and Havana. In each case the office is somewhat over one 

 mile from the cable hut at the water's edge. The submarine cable 

 circuit is connected to the apparatus in the offices through pairs of 

 wires in an underground cable of the paper-insulated lead-covered 

 type, which also carries the circuits of the older cables. In Fig. 8 



15 



20 25 30 



FREQUENCY IN KG. 



35 



40 



45 



50 



Fig. 5 — Attenuation of 1921 and 1930 cables. 



are shown schematically the connections of the whole cable com- 

 munication system. The arrangements are practically identical at the 

 two terminals except for differences incident to the fact that different 

 frequency bands are transmitted in the two directions. 



Certain coils and condensers are located at the cable hut. A trans- 

 former connects the unbalanced 50-ohm submarine cable to the 

 balanced-to-ground 130-ohm pair in the lead-covered cable. The 

 other coils and condensers form a "composite set" which connects 

 the submarine cable to a second pair in the lead-covered cable in order 

 to transmit direct current. This may be used as a d-c. telegraph 

 channel or as an insulation testing circuit. 



The carrier equipment in the telephone office may be considered in 

 two categories: (a) that which is derived from standard open-wire 

 carrier systems as described in the paper previously referred to, and 

 (&) that which is additional and special for this installation. 



