I N D EX A AGT, 1-4 AIS, 1-4 AIT,  1-4 ASC,  1-5 ASCII Code, 1-6 Authentication, 1-20 background, 1-20 AUTODIN, 1-2, 1-4 Automatic Switching Center, 1-5 background, 1-5 general teleprinter rules, 1-9 interfaces, 1-5 magnetic tape messages, 1-11 message accountability, 1-12 message formats, 1-11 message header, 1-7 message header programming, 1-6 message lengths, 1-9 misrouted and missent messages, 1-10 operating  precautions,  1-11 operating  rules,  1-11 operational modes, 1-5 routing indicators, 1-6 security,  1-12 suspected duplicates, 1-10 tape messages, 1-6 tape reel accountability, 1-12 transmission identification, 1-6 B BEADWINDOW,  2-8 BIUs, 1-2 C Circuit  procedures,  2-1 decimals, dates, and abbreviations, 2-4 discipline,  2-1 operating  signals,  2-8 phonetic alphabet, 2-3 phonetic numerals, 2-4 prowords,  2-5 punctuation, 2-4 techniques, 2-2 Circuit setup/restorations, 1-22 activate, 1-22 analyze networks, 1-22 background, 1-22 communications circuits, 1-22 deactivate, 1-22 OTAT/OTAR,  1-22 protocols, 1-22 shift frequencies, 1-22 standby,  1-22 Code and Cipher messages, 1-20 uses, 1-20 Command guard lists, 1-21 Common  User  Digital  Information  Exchange  System (CUDIXS), 1-15 message  accountability,  1-16 subscribers,  1-15 subscriber net cycle, 1-15 system interfaces, 1-16 system performance, 1-16 Communications Center administration, 1-20 circuit backlogs, 1-20 command guard lists, 1-21 communications plan (COMPLAN), 1-21 . INDEX-1