![Cisco DX650 Скачать руководство пользователя страница 98](http://html.mh-extra.com/html/cisco/dx650/dx650_administration-manual_64128098.webp)
Note
1
Adjusts dynamically when associating with an AP if the AP client setting is enabled.
2
Advertised rates by the APs are used. If the Restricted Data Rates functionality is enabled in the Cisco
Unified Communications Manager Administration phone configuration, then the Traffic Stream Rate
Set IE (CCX V4) is used.
For more information about supported data rates, Tx power and Rx sensitivity for WLANs, see the
Cisco
Desktop Collaboration Experience DX650 Wireless LAN Deployment Guide
.
Wireless Modulation Technologies
Wireless communications use the following modulation technologies for signaling:
Direct-Sequence Spread Spectrum (DSSS)
Prevents interference by spreading the signal over the frequency range or bandwidth. DSSS technology
multiplexes chunks of data over several frequencies so that multiple devices can communicate without
interference. Each device has a special code that identifies the data packets for the device and all other
data packets are ignored. Cisco wireless 802.11b/g products use DSSS technology to support multiple
devices on the WLAN.
Orthogonal Frequency Division Multiplexing (OFDM)
Transmits signals by using RF. OFDM is a physical-layer encoding technology that breaks one high-speed
data carrier into several lower-speed carriers to transmit in parallel across the RF spectrum. When used
with 802.11g and 802.11a, OFDM can support data rates as high as 54 Mbps.
The following table provides a comparison of data rates, number of channels, and modulation technologies
by standard.
Table 18: Data Rates, Number of Channels, and Modulation Technologies by IEEE Standard
802.11n
802.11a
802.11g
802.11b
Item
•
20 MHz
Channels: 7 -
72 Mbps
•
40 MHz
Channels: 15
- 150 Mbps
6, 9, 12, 18, 24, 36,
48, 54 Mbps
6, 9, 12, 18, 24, 36, 48,
54 Mbps
1, 2, 5.5, 11 Mbps
Data rates
13 or 24
Up to 23
3
3 (Japan uses 4)
Nonoverlapping
channels
OFDM
OFDM
OFDM
DSSS
Wireless
modulation
Cisco Desktop Collaboration Experience DX650 Administration Guide, Release 10.1(1)
80
WLAN Standards and Technologies
Содержание DX650
Страница 12: ...Cisco Desktop Collaboration Experience DX650 Administration Guide Release 10 1 1 xii Contents ...
Страница 20: ......
Страница 64: ......
Страница 116: ...Cisco Desktop Collaboration Experience DX650 Administration Guide Release 10 1 1 98 Wireless LAN Setup ...
Страница 172: ......
Страница 182: ...Cisco Desktop Collaboration Experience DX650 Administration Guide Release 10 1 1 164 Application Dial Rules ...
Страница 184: ......
Страница 196: ...Cisco Desktop Collaboration Experience DX650 Administration Guide Release 10 1 1 178 Status Menu ...
Страница 212: ...Cisco Desktop Collaboration Experience DX650 Administration Guide Release 10 1 1 194 Streaming Statistics ...
Страница 220: ......
Страница 228: ...Cisco Desktop Collaboration Experience DX650 Administration Guide Release 10 1 1 210 User Voice Messaging System Access ...
Страница 230: ...Cisco Desktop Collaboration Experience DX650 Administration Guide Release 10 1 1 212 International Call Logging Support ...