The name "validator" comes from the English valid - "valid, legitimate". This is a device that checks the authenticity of various documents, primarily at transport and checkpoints. Validators are electronic and electronic-mechanical.
To see the validator in action, buy a metro ticket or a one-time train ticket. Both metro stations and some railway stations are equipped with turnstiles, which have special devices that read information about a travel document. To get on the escalator, you need to go through the turnstile, attaching the travel card to a special luminous window. It can be located on the top or front panel of the turnstile.
Insert the train ticket with a barcode into the opening of the turnstile. Information about the ticket will go to the system, from there you will receive an answer that the passenger with such a ticket has not yet entered the platform, after which the green signal will light up and you will be able to go to the platform.
In large cities, buses, trolleybuses and trams are equipped with validators, primarily those that serve social routes. The portable validator is at the conductor's or driver's place. A passenger who has a contactless card (such as a social pass) gets on the bus and hands the document to the driver. The information about the boarding point is read by the device and transmitted to the electronic fare control system. Before getting off the bus or trolleybus, the passenger hands over the card a second time.
Stationary validators are also installed on land transport. They are located on the handrails. The passenger himself brings the ticket to the device, as a result of which a certain amount for the trip is debited from the card.
In modern information systems, validators of two types are used. A simple validator with the help of an LED indicator informs the passenger that the device is ready for operation, about payment or non-payment of travel, about the fact that the card has been applied again, as well as about blocking the ticket. The information validator, in addition to the same information, informs the passenger about the ticket. On the liquid crystal display, you will see information about the validity of the ticket, the number of remaining trips, the availability of funds. To get the information you need, pay your fare and then re-attach the card to the device. First, information will appear that the ticket has been reapplied, and then information about the travel document itself will appear on the screen.
Validators are used not only in transport. For example, similar devices are installed in many large chain stores. By attaching the product label to the reader, you can find out full information about the product - name, manufacturer, weight, cost.