Cell data glossary

Cell data networks are classified by generation; not surprisingly, each generation has been faster than the last. Here’s what the acronyms mean.

1G

Analog. Extremely slow, nearly discontinued.

2G

Digital voice service with data grafted on. Plain GSM, the dominant worldwide standard, can be used for 9,600-bps connections; GPRS can reach as fast as about 50 Kbps. 1xRTT, used by Verizon Wireless and Sprint but few other major carriers outside South Korea and Japan, is about as fast as a dial-up modem.

2.5G

EDGE (which works on existing GSM networks) offers rates as fast as 200 to 400 Kbps. It’s what the first-generation iPhone used. A next-generation EDGE technology that would cost carriers little to deploy could boost speeds beyond 1 Mbps, but it would require new chips in handsets and smart phones.

3G

The holy grail of cell data—for now. 3G networks run at broadband rates. The original 3G standards deployed were UMTS (for GSM networks) and EVDO Rev. 0 (for CDMA). AT&T offers service using the newer HSPA standard; Sprint and Verizon use EVDO Rev. A.

4G

Several standards are competing to see what will replace 3G. Sprint and Clearwire (a company founded by cellular legend Craig McCaw) recently agreed to a joint venture that plans to offer WiMax service—which can reach speeds of up to 15 Mbps—nationwide by 2010. AllTel (the country’s number five carrier), AT&T, T-Mobile, and Verizon have all committed to a GSM standard called LTE, but it won’t be commercially deployed until at least 2010.

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