srirao :
I have purchased samsung 2 duos, and using 2 sim.
If I make a call the call is going from SIM1, but I need to make a call from SIM2 directly from contacts. By default all the outgoing calls must be from SIM2.
Just stretch on the homescreen from upside to down.. where the options for turning on/off comes for wifi, bluetooth, GPS, etc appears. Below this there will be two icons "sim1" and "sim2". Just tap on "sim2" to select it as a default sim for texting or calling.