Short codes work similar to phone numbers when used on a mobile network, and callers input the numbers before pressing Send to identify the SMS message recipient. Because mobile phones codes do not require a set quantity of digits, they can send SMS messages to short codes, while landlines cannot.
Businesses commonly use short codes for promotions because they are easier to remember. Users send messages to short codes, which typically fall between four and six digits, to enter to win prizes or opt into SMS text messaging services. Companies may license short codes on a temporary or permanent basis, and a permanent code works well for established businesses that participate in many giveaways or have a popular name.
Short codes may appear on promotional materials as a series of letters, such as DISNEY, instead of numbers. Some phones can translate these codes into numbers, while others require users to puzzle out the numeric keypad entries for the alphabetic characters. Short codes are not the same on all wireless providers, and some providers do not support code inputs. Users who enter a short code and find themselves enrolled in an opt-in program for text messages can commonly opt out by texting STOP to the same short code.