1. How to insert two SIM Card?
Master SIM card : The SIM card used default , inseted into lengthwise SIM card slot.
Slave SIM card: The SIM card inserted into horizontal SIM card slot.

2. Usage of two SIM card for send or receive calls same time.
I. Pause ( Need Service Provider support). You can use this function to suspend current call and pick a new call up or make a new call at the same time.
II. Make a new call without hanging up currect phone call.
Duing a phone call , you can click the call key to hold the currect phone call and scroll down the left sotkey to menu list select the new call and key in phone number or use phone book to make your new call. To switch between Line 1 and line 2, you only need to select the 'switch' function . You can switch the line without hanging up you r current phone call.
III. Conference call function support. (Please check with your service provider)
IV. Insert Call.
If there is a call when you are on line. Just click 'send key' to pause the currect call and pick up the new call. You can switch the current line to other by clicking the oK key to sweitch. Push the end key to hang up th ephone call.(Please note this function works when it is supportd by your service provider)
V. Earphone
When you are using the earphone, you can pick up or end the phone call bu pushing earphone button. if you set the phone on Auto mode, the earphone will pick the phone up qutomatically in 1 second when a call is coming.