Sender ID is a set of characters that represents the identity of a sender. A Sender ID can have numbers,alphabets, or can even be alphanumeric. It is used to identify who is sending the message to the recipient. A Sender ID can be in the form of short codes or long codes. .The length of a Sender ID varies from country to country. Like in India the Sender ID would be of 6 characters while that in UAE and Saudi Arabia it could be upto 11 characters. The Sender ID also varies in the case of promotional and transactional SMS. A transactional SMS in UAE can have 11 character Sender ID whereas promotional SMS can have a 6 character Sender ID.