What does this international symbol stands for?

The international TTY/TDD symbol - typically showing a telephone handset placed on or combined with a keyboard device - specifically designates teletypewriter or text telephone equipment used by individuals who are deaf or hard of hearing. This symbol is standardized under ISO 7001 and referenced in ADA signage requirements to indicate the availability of text-based telephone communication. It is distinct from symbols used for standard voice telephones or internet access stations.

A public internet station uses a different symbol, typically depicting a computer monitor or globe, not a telephone handset with a TTY keyboard device.

A standard public telephone is represented by a simple telephone handset symbol without the additional keyboard or text-device element shown in the TTY/TDD symbol.

A public telephone with a shelfette would be indicated by a telephone symbol combined with a shelf or writing surface graphic, not the TTY keyboard representation.

High-speed internet access at a telephone would require additional iconography such as a signal wave or computer element, which is not what the TTY/TDD symbol depicts.