C.IKKIIR TlU.r.l'IlOW r).V ///(,// VOLTAGE I. IMS 177 



p.im-1 is till" Iransinittin^j e(|iiipiiH-i)t, \»>[\\ low powrr and IukIi power. 

 Tin- tifih paiu'l is {\w reruivinn rirniit; \hv sixth paiu-l ojiitains (ho 

 \oicf frefiiu'iiry and signaling i-ciuipim-nt. Tlir si-vonlh panel contains 

 D.l". control i'(iuipnu'nt, and the bottom panel is the low pass filler. 

 On the wall to the rijjlu of the carrier panel assembly are shown the 

 tilter coil unit and the filter and [irotector iniit. These imits are yn)re 

 clearly shown in Fig- 27 and diagrammaticalK- in Fig. 21 . Returning to 

 Fig. 2(i, the desk staiul which the operator is using is that associated 

 with the carrier eciuipment, while the key moimled on the table im- 

 mediately to the left of the desk stand is the selector key employed for 

 ringing. Fig. 1(> shows the coupling wire installation at this station. 



The power line carrier telephone eciuipment which has been briefly 

 tlescrit)ed in the foregoing article is in successful operation today on 

 se\eral power systems in this country. Its reliability, simplicity- of 

 operation and maintenance have been well established. 



The large number of variables which are involved in line failure 

 conditions make it impossible to predict what effect these emergency 

 contlitions may have on the operation of the carrier equipment. 

 The fact remains, however, that under many simulatefl and actual 

 trouble conditions successful operation of the carrier equipment has 

 been obtained. 



With the growing need of power companies for communication 

 facilities, it is probably only a question of a very short time before 

 multiple channel carrier, systems will be in operation on the large 

 power systems of this country. 



