Hello, The receptionist have a grandstream 2120 on her desk. When she gets the first call the phone rings, she picks up, and hit transfer-ext-send. During the blind transfer the call still blinks on her 2120 until other end of transfer picks up. During that time, if another call comes in the phone makes no noise. It just blinks red on line 2, however unless they are looking right at it they'll miss it everytime. Im running most current version of grandstream firmware and 3cx paid version up to date as well. The phone previously had some older firmware versions as well, but this issue has always been there no matter what firmware. I would really appreicate it if someone could help out on this one, thanks in advance.