578 BELL SYSTEM TECHNICAL JOURNAL 



rangement shown in Fig. 11. Each group of three bays mounts equip- 

 ment for one direction of transmission for 17 systems. A schematic 

 arrangement of equipment in a twist and flat gain regulating repeater 

 office is shown in Fig. 16. 



Auxiliary Repeater Station Equipment 



Each auxiliary repeater station houses crosstalk balancing equip- 

 ment, sealed test terminals, line amplifiers, pilot wire regulators, and 

 a power plant. A typical floor plan arrangement of the equipment re- 

 quired in one of these stations for a maximum of 100 systems is shown 

 in Fig. 17. The equipment arrangement for a 60-system route is 

 practically the same, except that provision has been made for a smaller 

 number of amplifiers and crosstalk balancing bays. A schematic ar- 

 rangement of equipment circuits is shown in Fig. 15. 



Four bays of sealed test terminals have been installed, one input and 

 one output for each direction of transmission. Initially each unit 

 contains carrier line and equipment jacks for testing or patching pur- 

 poses for 40 carrier and eight miscellaneous circuits. In addition, mis- 

 cellaneous auxiliary equipment is mounted in these bays. 



Twenty-one amplifier panels for one direction of transmission may be 

 mounted in a bay. Two bays are required for the flat gain master 

 controllers and the associated controller power supply equipment. 

 Figure 18-B shows amplifier, controller, and testing bays. 



High-frequency testing apparatus consisting of a variable test oscil- 

 lator and a portable transmission measuring set mounted in a mobile 

 relay rack bay has been provided at each auxiliary station. This unit 

 may be connected to the jacks in the sealed test terminals as required 

 by means of patch cords. 



Since auxiliary stations are designed to operate for considerable 

 periods of time without attention, the power plant is of the automatic 

 type.^ It consists of a 70-cell, 152-volt storage battery which is con- 

 tinuously floated across regulated tube rectifiers fed from a commercial 

 power supply. Figure 18-A shows a typical installation. Two recti- 

 fiers are provided initially, one which floats the battery, and the other 

 which is connected automatically into the charging circuit in case of 

 failure of the first unit or to increase the charging rate after a prolonged 

 failure of the outside power. Arrangements are available in the power 

 service cabinet to terminate leads from a portable emergency engine 

 driven alternator set which may be set up outside the building. It 

 is expected that the battery installed initially will be of sufficient size 

 to provide a minimum of 24 hours reserve throughout its life, taking 



