Well, if you keep the default value "Entering the Agent group" for "Event for connecting the call" AND "Regular ringback when agent rings" for "Ringback tone" (the very next field), you will achieve what you want. But as 'pbxnsip' mentioned in one of the earlier responses, the caller will be charged from the beginning. With these settings, the caller will be connected at the beginning itself, the 90 seconds issue will not arise.