TANDEM OPERATION IN THE BELL SYSTEM 



387 



Fig. 4 — Call indicator tandem position. 



Toll Office Tandems 



With the introduction of the combined line and recording method 

 of toll board operation, it was necessary to provide means for giving 

 each outward toll operator access to all of the toll circuits (instead of 

 circuits to certain points only, as required by the former single ticket 

 toll operating method) and in large toll offices where the transmission 

 and switchboard multiple limitations prevent multipling all of the 

 toll lines at the outward positions, toll office tandems provide such a 

 means. Toll office tandems also are used as a means for making toll 

 board circuits available to local operators, at both manual and dial 



