Technical Developments Underlying the Toll Services of the Bell System:A Supplement to the Bell System Technical Journal, July 1936

Page 2 4 5 6 9 10 13 14 15 22 26 30 34 34 36 37 38 39 39 43 46 46 46 46 47 47 48 48 48 49 49 49 50 50 51 52 52 54 54 57 58 65 66 68 69 69 70 71 71 72 Early Developments General--Telephone I n s t r u m e n t s Telephone Switching Systems Telephone Circuits a n d Cables E a r l y Toll Service T h e P h a n t o m Circuit Superposed Telegraph on Telephone Circuits Development of M a t h e m a t i c a l T h e o r y of Transmission--Loading I n t e r u r b a n Toll Cables Possibilities a n d Problems Associated with the Use of t h e Telephone R e p e a t e r . Toll Cable System .. T i m e F a c t o r in Telephone Transmission Multi-Channel Telephone Systems Associated Technical Developments Regulators Equalizers Signaling Systems Telegraph System Auxiliary A p p a r a t u s a n d E q u i p m e n t Development of M e t h o d s of Measurement a n d M a i n t e n a n c e for Toll C i r c u i t s . . Special Services--Program Transmission Telephotography Other Special Services Toll Operating M e t h o d s Operating M e t h o d Defined Interrelation of M e t h o d and E q u i p m e n t Design · · · Rearrangement of Plant Brought about by Changes in M e t h o d T r u n k i n g M e t h o d s Distinguished from Operating M e t h o d s Description of T r u n k i n g Methods-- Call-Circuit T r u n k i n g M e t h o d Straightforward T r u n k i n g M e t h o d Ringdown T r u n k i n g M e t h o d Dial T r u n k i n g M e t h o d Description of Toll Operating M e t h o d s General Characteristics of Toll Calls and Operating M e t h o d s A-Board Toll Operating Method T w o - N u m b e r Toll Operating M e t h o d Two-Ticket Toll Operating M e t h o d Single-Ticket Operating M e t h o d Combined Line a n d Recording ( C L R ) M e t h o d Evolution of Toll Operating M e t h o d s General Toll Switching Plan T h e Joint Occupancy of Plant Rental Arrangements Joint M a i n t e n a n c e Arrangements General.