Related Clues:

• Show Mexico designation on the computer
• What's often debugged
• Bar or Morse follower
• 'Inner-city' for 'black,' to some people
• Enigma machine's output
• Reading block?
• Secret sentences
• Passenger on vacation books train up for convention
• Approved procedure
• Create software
• Building inspector's reference
• It may involve an exchange of letters
• It's the custom for most of troops to reassemble in front of column
• Professional army officer keeping to correct procedure
• Etiquette image promoter introduces to senior officer