Mobile phone area codes are three digits long and always start with the number 9, although recently new area codes have been issued with 8 as the starting digit. Unlike fixed-line telephones, the long-distance telephone dialling format is always observed when using a mobile phone.Originally there were only three area codes for mobile phones: 917 for Globe Telecom, 918 for Smart Communications and 973 for Express Telecom, the three existing mobile companies at the time. As service began growing rapidly since the 1990s, new codes have been added to meet demand as existing codes have since been exhausted. Newer codes often come immediately after the last code exhausted, but this might not be the case if the next code is already in use. Areas codes are grouped by provider with no single contiguous block of codes for a single provider. These companies and their respective area codes are listed below: Key: