270 the bell system technical journal, january 1954 



Shannon, C. E.^ and E. F. Moore^ 



Machine Aid for Switching Circuit Design, I.R.E., Proc, 41, pp. 1348- 

 1351, Oct., 1953 (Alonograph 2153). 



Design of circuits composed of logical elements may be facilitated by auxili- 

 ary machines. This paper describes one such machine, made of relaj's, se- 

 lector switches, gas diodes, and germanium diodes. This macliine (called 

 the relay circuit analyzer) has as inputs both a relay contact circuit and the 

 specifications the circuit is expected to satisfy. The anah'zer (1) verifies 

 whether the circuit satisfies the specifications, (2) makes sj'stematic at- 

 tempts to simplify the circuit by removing redundant contacts, and also (3) 

 obtains mathematically rigorous lower bounds for the numbers and types 

 of contacts needed to satisfj' the specifications. A special feature of the 

 analyzer is its ability to take advantage of circuit specifications which are 

 incompletely stated. The auxiliary machine method of doing these and 

 similar operations is compared with the method of coding them on a general- 

 purpose digital computer. 



Smith, E. P.*', L. P. Cornell^ and M. G. Jerome^ 



Co-ordinating Ml and Nl Telephone Carrier Systems, Elec. Eng., 

 72, p. 780, Sept., 1953. 



Tanenbaum, M.^ and J. P. Maita^ 



Hall Effect and Conductivity of InSb Single Crystals, Letter to the 

 Editor, Phys. Rev., 91, pp. 1009-1010, Aug. 15, 1953. 



Templin, E. W., see J. G. Frayne. 



TowsLEY, L. M., see E. A. Wood. 



Tucker, C. J., Jr.^ 



Emergency Reporting System Installed by Southern Bell, Telephony, 

 145, pp. 26, 38, Aug. 29, 1953. 



New fire and emergency' rei)orting system utilizing telephone facilities for 

 the general public to make verbal reports of fires and other emergencies — 

 the first of its kind in the nation — was put into service in Miami, Fla., on 

 Aug. 1, by Southern Bell Telephone & Telegraph Co. 



Van Roosbroeck, W.^ 



1 Bell Telephone Laboratories. 



® Pacific Telephone and Telegraph Company. 



* Southern Bell Telephone Company. 



