HTC EVO View 4G 32GB User Manual page 23

Status Bar – Notification Icons
Music is playing
General notification (for example, sync error)
Storage card is low on free space
Wi-Fi is on and wireless networks are
available
Data synchronizing – connected to HTC
Sync
New location detected
More (undisplayed) notifications
Compass needs orientation
Uploading data (animated)
Downloading data (animated)
Waiting to upload
Status Bar – Notification Icons
Content downloaded
Device connected to computer via USB
cable
Storage card is safe to remove or storage
card is being prepared
No storage card installed in the device
New tweet
Updates available for an application
downloaded from Android Market
Status Bar – Device Status Icons
Signal Strength 
(More bars = stronger signal)
No Service
2A. Device Basics 11