There are many differences are there between 1x Rtt and 1x 
EVDO ----
1. first thing comes to mind the channel structure
in 1x RTT there are 4 forward channel and two rev channel . 
but in ev do that channel structure is different . control 
channel and the rest is total data

2. the basic and major difference is 1x RTT is based upon 
CDMA and 1x evdo is TDMA

3.