In the 1990s, the Greek company INTRACOM S.A. introduced the DKTL-4 digital call-charge indicator. It replaced the DT-2 model, which had been manufactured in the 1980s by the Greek company SIBER TELECOMMUNICATIONS S.A. It is made of dark-grey plastic. On the back—the side facing the customer making the call—there is a display showing the cost of the call in drachmas. Conversely, the front side features three buttons and a display; depending on how many times the left button was pressed, the screen would alternately show the call units, the cost of the call in drachmas, or the cumulative total of units. Pressing the middle button cleared the data from the previous call, allowing a new one to be made. Pressing the right button—labeled “BLOCK”—restricted the phone to local calls only; this status was indicated by a padlock icon appearing on the left side of the screen. On the base of the device, there is a sticker showing the required telephone network wiring configuration, the serial number, and the month and year of manufacture. Its dimensions are 6.5 cm x 13.5 cm x 14 cm. The sole customer for these devices was the Hellenic Telecommunications Organization (OTE S.A.), which managed the public telephone network.