not tested.. but have read that ...
sms is done on the same network as voice.
it is squeezed in between the voice calls on that system. it does not interrupt voice transmissions and very little space. that is why many argue that carriers should not charge for sms service... just a way to gauge the customers.
i do know...
when I dont have 3G or wifi .. google voice has a lot of trouble..
so i use the sprint text app and it works fine.
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