Telephone numbers in Singapore digits. Five digits were introduced in 1960s, whereas 5-digit and 6-digit phone numbers were introduced in 1960s as fixed lines grew, but in that year, these changed to seven digits as the introduction of new towns arose (Tampines, Jurong East, Bukit Batok, Yishun and Hougang) and a large number of new numbers were required. Rationalisation was based on geographical locale over the 12 years. In 1995, the digit '9' was added to the front of mobiland pager numbers, making numbers eight digits, and on 1 March 2002, the digit '6' was added to the front of existing fixed line telephone
Telephone numbers in Bulgaria beginning with a "4") invariably require the "02" city code. Until 20 July 2003 GSM networks used six-digit subscriber numbers in accordance with the limit of eight digits for the domestic part of a number. With the increase of subscribers (and an international requirement), all (except Vivacom, which started operations in 2006) acquired new access codes. On 20 July 2003, Mobiltel used three codes ("(0)87", "(0)88", "(0)89") and Globul used two ("(0)98" and "(0)99"). When these limits were also to be overwhelmed, seven-digit subscriber numbers and single access codes per operator were introduced, hence M-tel reverted to 088 (+7 digits)"