Domestic numbers are limited to eight digits in length. Area codes vary in length from one to five digits. Subscriber number lengths vary accordingly, from seven digits down to three digits. Sofia lines on digital switches have seven-digit numbers, analog six; in Plovdiv, Varna and Ruse both are six digits; and in most other province capitals lines on digital switches have six-digit numbers and analog five.For a very long time, the state-owned Bulgarian Telecommunications Company (BTC) had a monopoly on fixed telephone networks. However, it ended when a special law was adopted. BTC was privatized in 2004 and competing operators appeared. Larger areas, such as Sofia, Plovdiv, Varna, and Burgas, are subdivided into zones. Although one cannot further reduce the number of dialed digits, the number itself shows which zone it is located in. For example, in Sofia, numbers starting with 2 , 82 , 92 are located in the Western suburbs, 7 , 87 , 97 in the Eastern suburbs, and 98 in the central area. In the recent decade there is an intensive process of replacing the old analog switches with modern digital ones. In areas where both analog and digital switchers are operating, a subscriber number shows by its first digit if it is connected to an analog or a digital switch. In some areas it is even possible to guess if a subscriber number was changed from analog to digital during its existence or was subscribed as digital initially. For example, in Blagoevgrad a number starting with 88 was subscribed as digital, and a number starting with a single 8 was analog before. The first digit also shows if a particular subscriber number is operated by BTC or another operator. The area codes are always cited with the trunk code. However, within the area, or when the Sofia code of (0)2 can be guessed from the context, it is omitted.