A system that incorporates both outbound (Mobile Terminated or MT) and inbound (Mobile Originated or MO) SMS into one fully-featured service. By using a dedicated number, a 2-Way SMS user can send and receive SMS through a web messaging platform by using complete solutions or APIs.
2-Way SMS messaging is done using short codes or virtual long numbers (also known as virtual mobile numbers). The main difference between the two is the length of the number; while virtual mobile numbers look like a standard phone number, short codes have between 3 and 6 digits, making them easier to remember.
Short codes can only be used on a national level and countries around the world have different regulations and requirements concerning them.