Related Clues:

• Kind of alphabet
• Kind of signals
• Code name
• 'Tru' Tony winner
• Kind of code
• Tony-winning actor of 1962 and 1990
• Lewis's mystery-solving partner
• Code inventor
• Telegraph developer Samuel
• Code creator
• David of 'Hack'
• Eponymous code creator
• Telegraph pioneer
• Samuel with a code
• Telegraphy pioneer