In the 1970s, the Greek company Geniki Promitheftiki (Constructions) Hidiroglou-Lambrou S.A. (a manufacturer of electrical and telecommunications equipment and plastic products) introduced the TL 1602-3 analog call-cost indicator. The company began operations in 1955, focusing on the import and representation of electrical and telecommunications equipment. In 1968, he established a manufacturing plant in Oinofita, Boeotia, for high-tech electrical, electronic, and telecommunications equipment, specialized industrial applications, and national defense hardware. By 1987, the company had become one of the most significant Greek enterprises in its sector, counting the Public Power Corporation (D.E.H), OTE, the Ministry of National Defense, and the Ministry of Finance among its clients. It employed 70 people on a permanent basis. It consists of two analog displays (using mechanical relays, similar to old odometers): the upper one calculates the total number of telephone units used, while the lower one tracks the units for a single call. Two buttons—one red and one white—are located at the top of the device to reset the displays. The device connects to the telephone network at the rear. It is made of light-gray plastic. A label on the base of the device displays the model, the company name, and the charging pulse frequency. Its dimensions are 7 cm x 11 cm x 9 cm. The sole customer for these devices was the Hellenic Telecommunications Organization (OTE S.A.), which managed the public telephone network.