hi friend i had SGG i month of using it and i realize the same issue, although company say it ia dual sim but in my case not both sim active at same time but not if one busy. both phone s duos and grand duos had single radio modem( transmitter ) that is why if u using one sim you cant get call from other sim (using include net using like FB skype) . i use my 1st sim for net and second for calling if i use net and simultaneously there is call on other sim it simply respond as busy user to the caller for using the service you have to activate call forwarding on both sim to receive call on both sim but its chargeable although its depend on you that you pic that call or not but atleast you get a notification of call on other sim .
Hi dear. You mis understand me. I know about all that you mention but this is not what I ask about. I does not mean when "other call me" as you mention. I ask about what happen "when I call other".
You can help me if you answer: does you suffer from failure when YOU CALL OTHER from one of yuour 2 sim card or not? I mean by failure: you may need multiple trail to call someone & this not happen if you use same card but in other phone.