WIRE LINE SYSTEMS FOR NATIONAL BROADCASTING 147 



the various chains are interconnected and arranged for switching at 

 certain distributing centers. 



In the United States the largest distributing center is, naturally, 

 in New York City, since the bulk of the program material originates 

 at that point. At such a distributing center a special collection of 

 various forms of equipment is provided consisting of one-way ampli- 

 fiers, loud speakers, multifrequency oscillators, various forms of trans- 

 mission measuring devices and miscellaneous apparatus. The photo- 

 graph of Fig. 5 shows a portion of the program layout in the New 



Fig. 5 — Portion of Program Apparatus Layout in New York Long Distance 

 Telephone Office as of January 15, 1929. 



York long distance telephone office as of January 15, 1929. The 

 various bays at the left carry the line apparatus associated with 

 branches of various chains. In the rear are located the transmission 

 measuring apparatus and multifrequency oscillators. In the fore- 

 ground are the terminals of various telegraph order wires. 



In transmitting programs over a wire network, as has been pointed 

 out above, it is important that the volume range be held within 



