1xRTT

From CDGWiki

1xRTT – cdma2000 Radio Transmission Technology

a.k.a. cdma2000 1xRTT, cdma2000 1x, 1x, TIA-2000, IS-2000

A version of cdma2000 specified in TIA-2000 (3GPP2 C.S0001-C.S0006) that provides voice and low speed data service using a single 1.25MHz channel (hence the “1x”). 1xRTT almost doubles voice capacity over IS-95 networks and supports data up to 144Kbps. Though it is a 3G technology, it is sometimes referred to as 2.5G. From a network perspective, procedures to support voice roaming using either 1xRTT or CDMA (IS-95) are the same.