TTY

TTY (Teletypewriter) is a communication system used in Payphone Tag that allows text to be transmitted over telephone lines using encoded audio signals.

In the context of Payphone Tag, TTY is primarily used through certain Telstra Smart Payphone units that include a physical slide-out keyboard.

A full list of all TTY capable payphones according to Telstra can be found at Category:TTY-equipped payphones.

Usage in Payphone Tag

When a TTY-capable payphone is captured, the Operator may initiate TTY mode after the login sequence. If the payphone supports it, the TTY keyboard can slide out, allowing the agent to type a message.

The typed message is transmitted as an ITA2 (Baudot) encoded signal over the phone line. The game backend decodes this signal and posts the message in real time to the Discord Server’s #tty channel.

Forcing TTY mode

Agents can also manually trigger TTY mode on most payphones by:

• Entering * after login is complete (the operator does not currently support entering it immediately after the PIN.)
• Playing a pre-encoded ITA2 audio file into the handset or using a portable TTY device to generate encoded signals live.

This allows messages to be injected into the system without requiring a physical TTY keyboard.

Technical details

• Encoding: ITA2 (Baudot code)
• Baud rate: 50 baud
• Mark frequency: 1410 Hz
• Stop frequency: 1820 Hz
• Stop bits: 1.5
• Transmission: Audio tones over phone line
• Output: Decoded and displayed in Discord

Limitations

Not all TTY-enabled payphones function correctly. Many units connected via cellular (4G) networks have been reported to fail when attempting TTY communication.

Real-world context

TTY systems were historically used to assist deaf or hard-of-hearing users in communicating via telephone networks, among other uses.

See also

• Payphone Tag Discord Server
• Telstra Smart Payphone
• Gameplay