604 



BELL SYSTEM TECHNICAL JOURNAL 





Figure 26 - Arrangenient 

 of line equipment in one as- 

 sembly for type " C " carrier 

 telephone. (Front view) 



top to bottom the panels are input filters, 

 auxiliary filters, equalizers, auxiliary ampli- 

 fier, two regular amplifiers separated by a 

 jack panel, and output filters. The arrange- 

 ment of filters and equalizers is chosen to 

 minimize any tendency toward inductive 

 feed-back effects between the output and 

 input circuits of any one repeater as well as 

 crosstalk between different repeaters on ad- 

 jacent bays. 



The pilot channel equipment at a carrier 

 repeater station is similar to that employed 

 at the terminal stations, excepting that the 

 alarm and oscillator panels are not included. 

 The alarm apparatus is omitted in this case, 

 since it is not the practice to have the car- 

 rier repeater attendants readjust the carrier 

 repeaters to take account of line changes, 

 excepting when instructed to do so by the 

 attendants at the terminal stations where the 

 alarm apparatus is installed. The pilot chan- 

 nel equipment at each repeater station thus 

 consists principally of an indicator panel as- 

 sociated with the transmission circuit in 

 each direction, which is assembled with the 

 other equipment as previously shown at the 

 extreme right in Figure 24. 



Line Equipment. Figure 25 shows the 

 principal line equipment units which are 

 closely associated in effecting connection 

 between the high-frequency circuit of the car- 

 rier system and the voice-frequency line. 

 This equipment, consisting of the line filters, 

 composite sets, and entrance and office load 

 coils, is mounted together in one assembly 

 and located as near as practicable to the 

 other carrier equipment. A method of as- 

 sembly which is now under development is 

 shown in Figure 26. The bay shown con- 

 tains the line equipment for two phantom 

 groups. 



This compact method of assembling and 

 wiring the line equipment reduces the amount 

 of ofifice cabling required for the carrier and. 



