A Short Code is a 3-6 digit number that allows sending and receiving SMS messages within state borders in SMS sweepstakes, polling, TV voting, etc. SMS messages are leased both from mobile network operators or by specific messaging companies that also give consultancy and tech support.
There are two types of short codes ー dedicated, i.e. used by only one company, and shared which can be used by several companies having their campaigns be known by keywords. For example, one company can use the number to receive SMS messages with the SUPPORT keyword, and other company can use it to receive messages with the PIZZA keyword. These keywords provide the matching of inbound messages with needed campaigns.