From there, smsBikeShare was born. Users registered with a mobile phone number and could send basic SMS commands (RENT, RETURN, FREE, WHERE, etc.). The system used an inexpensive SMS gateway API and a local message-back number to receive and respond to messages. Shared bicycles have a coded U-lock with a four-digit number, and upon renting a bike, users receive a code to unlock the bicycle and another to reset it to once they are done.
Send a message, receive the answer, unlock the bike, reset the lock, and you're off pedaling."
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