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Cisco Unified Wireless IP Phone 7925G Administration Guide for Cisco Unified Communications Manager 7.0(1)
OL-15984-01
Chapter 2 Overview of the VoIP Wireless Network
Understanding WLAN Standards and Technologies
Wireless Modulation Technologies
Wireless communications uses 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 its data packets and all others are ignored. Cisco wireless 802.11b/g
products use DSSS technology to support multiple devices on the WLAN.
Ta b l e 2-2 Tx Power, Data Rates, Ranges, and Decibels by Standard
Standard
Maximum
Tx Power
1
1. Adjusts dynamically when associating with an AP if the AP client setting is enabled.
Data Rate
2
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.
Range
Receiver
Sensitivity
802.11a
40mW 6 Mbps 610 ft (186 m) -89 dBm
9 Mbps 610 ft (186 m) -88 dBm
12 Mbps 558 ft (170 m) -86 dBm
18 Mbps 541 ft (165 m) -85 dBm
24 Mbps 508 ft (155 m) -82 dBm
36 Mbps 426 ft (130 m) -80 dBm
48 Mbps 328 ft (100 m) -76 dBm
54 Mbps 295 ft (90 m) -74 dBm
802.11g
40mW 6 Mbps 722 ft (220 m) -90 dBm
9 Mbps 656 ft (200 m) -89 dBm
12 Mbps 623 ft (190 m) -87 dBm
18 Mbps 623 ft (190 m) -85 dBm
24 Mbps 623 ft (190 m) -82 dBm
36 Mbps 492 ft (150 m) -78 dBm
48 Mbps 410 ft (125 m) -74 dBm
54 Mbps 394 ft (120 m) -73 dBm
802.11b
50mW 1 Mbps 1,027 ft (313 m) -95 dBm
2 Mbps 951 ft (290 m) -89 dBm
5.5 Mbps 853 ft (260 m) -89 dBm
11 Mbps 787 ft (240 m) -85 dBm
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