Door - card convenience enabling the reading of the remaining unit box, to avoid the stop in a cabin convenience warned by an audible beep

摘要

A siren (4) indicates the withdrawal of the card and a compartment on the rear or the casing (1) is used to feed the device. The casing incorporates a printed circuit for the following functions: time, date, units, deduction of units used and siren indicating that the telephone card has been withdrawn from its casing by a bleep every 5 to 10 seconds. Feed is by means of a battery fitted in its compartment on the rear of the casing. The face (2) permanently shows the time and date, causing the number of units to disappear and making the word 'units' to flash when the card is withdrawn from the casing, activating the audible siren. When the card is replaced in its casing it shows the units detected and stops the function of the siren.