The term BUS. CARD INFO is composed of three parts: EXT (3 letters), TEL (3 letters), and PHONENO (7 letters). EXT stands for extension, which is a number that is added to the end of a telephone number to direct the call to a specific person or department. TEL stands for telephone, which is a device used to make and receive calls over a distance. PHONENO stands for phone number, which is a unique combination of numbers used to identify a particular telephone line. Together, these three terms refer to the information typically found on a business card, such as an extension, telephone number, and phone number.