Physical Specifications

• The iPAQ 6945 and the iPAQ 6515 both have a bar -- or candy bar -- form factor and rely on a centrally located joystick as their primary navigation button. In addition, the two smartphones have identical physical dimensions of 2.8 inches wide by 0.7 inches deep by 4.6 inches high. The main physical difference between the two smartphones is that the iPAQ 6945 weighs 6.2 oz., while the iPAQ 6515 is lighter at 5.8 oz.
  
  

Cellular Technology

• For sending and receiving data, both the iPAQ 6945 and the iPAQ 6515 utilize a Global System for Mobile Communications network. More specifically, the smartphones are compatible with quad-band GSM, which means they can operate over the 850, 900, 1,800 and 1,900 frequency bands. GSM functions utilizing Time Division Multiple Access cellular technology. This technology divides individual radio frequencies into multiple slots of time and then assigns those slots to carrying data signals. The iPAQ 6945 and the iPAQ 6515 both support the third-generation General Packet Radio Service and Enhanced Data Rates For Global Evolution standards, which allow the smartphones to access the Internet using cellular signals.
  
  

Connectivity

• One of the primary differences between the iPAQ 6945 and the iPAQ 6515 is that the former can connect to wireless local area networks for accessing the Internet, while the latter cannot. More specifically, the iPAQ 6945 is compatible with the IEEE 802.11b Wi-Fi standard for wireless Internet connectivity. Both smartphones can utilize Bluetooth and Infrared Data Association technologies for communicating wirelessly with headsets, computers, printers and other devices.
  
  

Operating System and Memory

• The iPAQ 6945 comes standard with the Pocket PC Phone Edition of the Microsoft Windows Mobile 5.0 operating system. In comparison, the iPAQ 6515 comes standard with the Pocket PC Phone Edition of the older Microsoft Windows Mobile 2003 Second Edition operating system. However, while the iPAQ 6945 provides 45MB of user memory, the iPAQ 6515 provides 55MB of user memory. Higher amounts of user memory allow users to download and store more files and data.
  
  

Camera and Display

• The cameras and display screens of the iPAQ 6945 and the iPAQ 6515 have identical specifications. Both cameras can capture still images in the JPEG format using 1.3 megapixels, or 1.3 million tiny squares of illumination. In addition, both cameras have maximum still image resolutions of 1,280 horizontal lines of pixels by 1,024 vertical lines of pixels. The display screens of the iPAQ 6945 and the iPAQ 6515 rely on an active-matrix variety of liquid-crystal display technology known as thin-film transistor. The TFT displays of both phones have resolutions of 240 pixels by 240 pixels and can display 65,000 colors.