ZyXEL 2WG Guida Utente

Chapter 8 WAN and 3G Screens

ZyWALL 2WG User’s Guide

See the following table for a comparison between 2G, 2.5G, 2.75G and 3G wireless 
technologies..

Table 45   2G, 2.5G, 2.75G, 3G and 3.5G Wireless Technologies

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.