It is generally assumed that a telephone number for voice communication is a sequence of digits. However, since the keys on the dialing keypads of telephones and cell phone keypads are also assigned letters, a phone number can also be entered in the form of a name. This type of entry is called a vanity number.
The International Telecommunication Union( ITU) has defined the letter assignment of the number keys. According to this, no letters are assigned to the numeric keys 0 and 1. The letters "A", "B" and "C" are assigned to the numeric key "2", the letters "D", "E" and "F" to the numeric key "3", and so on. Generally, each letter is entered by pressing the same key one or more times. The letter "E", which is assigned to the numeric key "3", is called by pressing it twice - because it is in the second position. Since this procedure is too time-consuming for entering a vanity number, programs such as T9 support a simplified entry where each key is pressed only once.
For a personal 0700 number, the entry could look like this: 0700-MUSTER, instead of 0700-687837, keeping in mind that the combination of digits corresponding to the desired name or company name must be requested.