When using the iPhone, the device has several symbols that appear at the top of the screen in the status bar, called status icons. Status icons convey information about the services the iPhone is currently using. Four different triangle-shaped status icons may appear at the top of the iPhone, each meaning something different.
When you play media on the device, the iPhone displays the "Play" icon in the status bar on the screen, just to the left of the battery icon. The "Play" icon resembles a right-facing triangle and appears when the iPhone plays any type of media including YouTube videos, iPod music or Internet radio applications.
Location Service Icon
Location service is a feature available on the iPhone that uses network connectivity, Wi-Fi connectivity and GPS to show the current location of the iPhone. When you use an application that employs the location-service feature, the location-service status icon appears in the upper right corner of the status bar, to the left of the battery icon. The location service icon is a triangle-shaped icon that resembles a right-facing mouse pointer.
Cell Signal Icon
The cellular signal status icon appears in the upper left corner of the status bar as long as the phone has cellular service. The cell signal icon, made up of five progressively larger vertical bars, resembles a triangle somewhat. When the phone has a weak cellular signal the triangle appears smaller; when the phone has a stronger cellular signal, the triangle appears larger. The "No Service" status message replaces the cell signal status icon if the phone is not within range of a cellular signal.
The Wi-Fi status icon appears in the status bar when the iPhone connects to a Wi-Fi network. The Wi-Fi icon appears on the left side of the status bar directly to the right of the cellular provider's name and is a triangle-shaped icon made up of three curved horizontal bars that get progressively larger. Much like the cellular signal icon, the Wi-Fi icon appears smaller when the phone has weaker Wi-Fi connectivity and larger when the phone has stronger Wi-Fi connectivity. The Wi-Fi status icon disappears when not connected to a Wi-Fi network.