ZyXEL Communications ZyWall USG 50-H Series, Руководство пользователя

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Chapter 8 Interface
ZyWALL USG 50-H User’s Guide
171
8.7 Cellular Configuration Screen (3G)
3G (Third Generation) is a digital, packet-switched wireless technology. Bandwidth usage is
optimized as multiple users share the same channel and bandwidth is only allocated to users
when they send data. It allows fast transfer of voice and non-voice data and provides
broadband Internet access to mobile devices.
"
The actual data rate you obtain varies depending the 3G card you use, the
signal strength to the service provider’s base station, and so on.
If the signal strength of a 3G network is too low, the 3G card may switch to an available 2.5G
or 2.75G network. See the following table for a comparison between 2G, 2.5G, 2.75G and 3G
of wireless technologies.
To change your 3G WAN settings, click Network > Interface > Cellular .
Table 52 2G, 2.5G, 2.75G, 3G and 3.5G Wireless Technologies
NAME TYPE
MOBILE PHONE AND DATA STANDARDS
DATA
SPEED
GSM-BASED CDMA-BASED
2G Circuit-
switched
GSM (Global System for Mobile
Communications), Personal Handy-
phone System (PHS), etc. Interim Standard 95 (IS-95), the first
CDMA-based digital cellular standard
pioneered by Qualcomm. The brand
name for IS-95 is cdmaOne. IS-95 is
also known as TIA-EIA-95. Slow
Fast
2.5G Packet-
switched GPRS (General Packet Radio
Services), High-Speed Circuit-
Switched Data (HSCSD), etc. CDMA2000 is a hybrid 2.5G / 3G
protocol of mobile telecommunications
standards that use CDMA, a multiple
access scheme for digital radio.
CDMA2000 1xRTT (1 times Radio
Transmission Technology) is the core
CDMA2000 wireless air interface
standard. It is also known as 1x, 1xRTT,
or IS-2000 and considered to be a 2.5G
or 2.75G technology.
2.75G Packet-
switched Enhanced Data rates for GSM
Evolution (EDGE), Enhanced GPRS
(EGPRS), etc.
3G Packet-
switched
UMTS (Universal Mobile
Telecommunications System), a third-
generation (3G) wireless standard
defined in ITU
A
specification, is
sometimes marketed as 3GSM. The
UMTS uses GSM infrastructures and
W-CDMA (Wideband Code Division
Multiple Access) as the air interface.
CDMA2000 EV-DO (Evolution-Data
Optimized, originally 1x Evolution-Data
Only), also referred to as EV-DO, EVDO,
or just EV, is an evolution of CDMA2000
1xRTT and enables high-speed wireless
connectivity. It is also denoted as IS-856
or High Data Rate (HDR).
3.5G Packet-
switched HSDPA (High-Speed Downlink Packet
Access) is a mobile telephony
protocol, used for UMTS-based 3G
networks and allows for higher data
transfer speeds.
A. The International Telecommunication Union (ITU) is an international organization within which governments and the private sector
coordinate global telecom networks and services.