Nokia E51 User Manual page 20

Get started
The connection to a headset with Bluetooth connectivity
has been lost.
A hands-free car kit is connected to the device.
A loopset is connected to the device.
A text phone is connected to the device.
Your device is synchronising.
You have an ongoing push-to-talk connection.
Your push-to-talk connection is in the do not disturb
mode, because the ringing type setting of your device is set
to Beep once or Silent, or you have an incoming or ongoing
phone call. In this mode, you cannot make PTT calls.
20 © 2007 Nokia. All rights reserved.