CDMA2000

Enhancements to the CDMA wireless cellphone technology that allow data to be transmitted. In 2000, CDMA2000 was the first 3G technology to be commercially deployed as part of the ITU's IMT-2000 framework (see IMT-2000). By 2006, the CDMA Development Group (CDG) reported that the international CDMA2000 subscriber base had surpassed 185 million users.

1xRTT
The first version of CDMA2000 provides data rates of 307 Kbps (downlink) and 153 Kbps (uplink) as well as twice the voice capacity on a single 1.25 MHz CMDA channel in new or existing spectrum. The use of the single channel is known as "1X" or "1xRTT" (1X Radio Transmission Technology). It is also known as "IS-2000," "MC-1X," and "IMT-CDMA MultiCarrier 1X."

1xEV (1xEV-DO and 1xEV-DV)
1xEV technology provides higher speeds implemented in two phases. Phase 1 is Evolution-Data Only (1xEV-DO), which increases the downlink peak data rate to 2.4 Mbps. The average rate a user experiences is between 300 and 600 Kbps. 1xEV-DO Revision A supports IP packets, increases the downlink to 3.1 Mbps and boosts uplink dramatically to 1.2 Mbps.

Phase 2 is Evolution-Data Voice (1xEV-DV), which integrates voice and data on the same carrier with rates up to 4.8 Mbps.

3x
CDMA2000 3x uses three 1.25 MHz CDMA channels. It is part of the CDMA2000 specification for countries that require 5 MHz of spectrum for 3G use. CDMA2000 3X is also known as "3XRTT," "MC-3X," and "IMT-CDMA MultiCarrier 3X." See CDMA, WCDMA and cellular generations.

1X Signal Strength

The "1X" is the 1xRTT signal strength on this cellphone, which is only one bar at this moment. The "EV" signal, also one bar, is the 1xEV-DO channel. As the phone travels, the strength of the two signals may differ.