About TTY support
When you turn on TTY support and you connect your BlackBerry® device to a TTY device that operates at 45.45 bits per second, you can make calls to and receive calls from TTY devices. Your BlackBerry device is designed to convert received calls to text that you can read on your TTY device.
If your TTY device is designed for use with a 2.5 mm headset jack, you must use an adapter accessory to connect your TTY device to your BlackBerry device. To get an adapter accessory that Research In Motion has approved for use with your BlackBerry device, visit www.shopblackberry.com.