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Networking Hardware Considerations for Windows Network Projectors (Windows Embedded CE 6.0)

  • 아티클

1/5/2010

For wireless connectivity, Windows Network Projectors must support the specified protocols to interact with an 802.11-compliant Windows Vista-based PC. Specifically, support for WPA2-compliant 802.11g networking is required. A premium wireless projector device should additionally support the IEEE 802.11a wireless standard. Support for wired networking is optional. Two networking cards are required within, or connected to, a network projector to enable it to simultaneously connect to both a wireless Windows Vista-based PC and a LAN.

Wireless Networking

802.11a

IEEE 802.11a operates at a data transmission rate as high as 54 megabits per second (Mbps) and uses a radio frequency of 5.8 GHz. Instead of DSSS, 802.11a uses orthogonal frequency-division multiplexing (OFDM). OFDM allows data to be transmitted by sub-frequencies in parallel. This modulation mode provides better resistance to interference and improved data transmission. This higher-speed technology improves WLAN networking performance for video and conferencing applications and for future streaming video support.

802.11b

IEEE 802.11b, an enhancement to IEEE 802.11, provides standardization of the physical layer to support higher bit rates. IEEE 802.11b uses 2.45 GHz, the same frequency as IEEE 802.11, and supports two additional speeds, 5.5 Mbps and 11 Mbps. It uses the DSSS modulation scheme to provide higher data transmission rates. The bit rate of 11 Mbps is achievable in ideal conditions. In less-than-ideal conditions, the slower speeds of 5.5 Mbps, 2 Mbps, and 1 Mbps are used.

802.11g

IEEE 802.11g is an extension to 802.11b and supports bandwidth up to 54 Mbps, using the 2.4 Ghz frequency for greater range. 802.11g is backwards compatible with 802.11b, meaning that 802.11g access points will work with 802.11b wireless network adapters and vice versa. When there is contention for bandwidth, 802.11g falls back to 802.11b to allow for 802.11b devices to operate. The presence of an 802.11b participant significantly reduces the speed of an 802.11g network impacting the performance of wireless data transfer.

Wired Networking

Support for wired networking is optional for Windows Network Projectors. Providing support for a wired network connection for a Windows Embedded CE based projector or display offers the option to connect to a corporate LAN. A wired interface will require a 10/100 Mbps 10BaseT/100BaseT (IEEE 802.3/802.3u) network connection. To reduce costs, you can attach an Ethernet connector or Ethernet header.

If needed, you can connect an Ethernet debug port to the Ethernet connector or Ethernet header for development and debugging purposes. Attaching an Ethernet connector or Ethernet header allows you to save the cost of including an Ethernet debug port in every hardware platform. The following list shows the requirements for the network controller:

  • Auto-detection and auto-switching between the 10 Mbps and the 100 Mbps data transfer rates.
  • Detection when the network cable is disconnected.
  • Support for direct memory access (DMA) transfers to system memory up to the maximum bandwidth allowable by the IEEE 802.3/802.3u specification.

See Also

Other Resources

Performance Considerations for the Hardware Components of Windows Network Projectors