Originally Posted by NeoteriX

I tested on the Evo LTE with SMS (not MMS):

1) All antennas on (BT, WIFI, "Mobile Network") texts send (obviously)

2) With WIFI off and "Mobile Network" off (and within the Mobile Network settings, "Domestic Data" and "Domestic Voice" off), texts send -- lending evidence that texts are not 3G dependent but instead are ok on 1xRTT.

3) With "Airplane Mode" on, texts do not send.

4) With "Airplane Mode" on and Wifi turned ON, texts do not send. Evidence that regular texts will not send over Wifi. However, Google Voice texts (that solely rely on data) do send.


Based on this, I'm pretty sure SMS is transmitted by 1xRTT only.