Possible Clues:

• Sign-off letters before L
• Communication syst. for the deaf
• Phone communication system for deaf and hard of hearing people
• "__L": "Bye for now"
• Telephone device used less widely since the invention of smartphones (Abbr.)
• Communication device for the deaf: Abbr
• Letters that aid the deaf
• Erstwhile newsroom machine: Abbr.
• Communications syst. for the deaf
• Device for the deaf, for short