446 the bell system technical journal, april 1951 



Power Supply 



The power supplies required for the N-1 system may be obtained from 

 standard office signahng or telegraph power plants without additional filter- 

 ing. The terminal equipment requires —48 volt and +130 volt supplies. 

 Repeaters located at power supply points require +130 volt power only. 

 For feeding pwwer over the line to distant repeaters +130 volt and —130 

 volt supplies are used in combination as a 260 volt source. 



Alarms and Order Wire Equipment 



Each system terminal makes provision for the following alarms which 

 are connected to the standard office alarm system: 



a. Fuse alarms for all battery supplies. 



b. 3700 cycle signal oscillator failure alarm. 



c. Alarm which indicates failure to receive carrier at terminals. 



The equipment for these alarm circuits is assembled as part of the ter- 

 minal mounting with all wiring accessible from the front of the relay rack. 

 Similarly at the repeater point where power is locally supplied the associated 

 power distribution panel is equipped with fuse alarm circuits for the battery 

 supplies. 



No alarms are provided at or from non-power supply repeater points. 

 Alarms from an unattended or partially attended repeater office can be 

 extended to a fully attended office, when desired, over one pair of a quad 

 in the cable which has its side circuit equipped with H88 or HI 72 loading. 

 The other pair of this quad may be used as an order wire for system main- 

 tenance. The simplex legs of the two pairs are used to transmit power from 

 power supply points to the portable repeater switching set used at pole- 

 mounted repeaters. The equipment arrangement for the order wire and 

 alarm circuits makes use of the conventional panel method of mounting 

 and provides for a variety of layouts to fit particular applications. Amplifiers 

 are introduced into the order wire and alarm circuits at terminals and power 

 supply repeater points as required. At pole mounted repeaters the order 

 wire equipment consists only of a pair of binding posts for connecting a 

 lineman^s test set. 



