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BELL SYSTEM TECHNICAL JOURNAL 



apparatus which may be required to suit each case. While this ar- 

 rangement will have its chief advantages when applied to large cable 

 installations, it will also be well suited to open-wire use and small 

 installations, since its design will permit the highest degree of flexi- 

 bility with respect to both the amount and type of equipment. 



These points may be illustrated by comparing the general features 

 of the two types of boards. Fig. 14 shows the assembly of a one- 

 position section of the present type of board employing a wooden 



TTST CORD PLUGS 



' ..l.i, TflEGRAPH KEYS 



Fig. 15 — Typical General Assembly 

 of Panel Mounted Test Board 



Fig. 16 — Typical Assembly for Keyshelf 



Equipment Unit for Panel Mounted 



Test Board 



framework. This board, with the necessary allowances for aisle 

 space, requires a floor area amounting to about 24 square feet, while 

 it houses a maximum of about 1000 jacks corresponding roughly to 

 about 40 jacks per square foot. Fig. 15 shows a typical position em- 



