The telephone charge meter or call unit meter was a device used in telephone line to record 16 kHz billing pulses. Connected to the telephone line, it recorded the pulses—factoring in both the duration and distance of a call—and displayed the billing units (e.g., one unit for a local call) as well as the calculated cost of the call in drachmas. They were used in public telephones (in phone booths, at newsstands, and in coffee houses) until the late 1990s. Until the mid-1980s, the telephone charge meter was analog, but around the end of that decade, the units were replaced by digital displays. Today, it too has become a part of telecommunications history.