Incoming call delay
This may help....
Somethings to consider:
1- I would say the actual ring signal is not always synchronized with the ring back tone we heard. The may come from different system within a complex telecom network. Therefore, some delay is expected as normal functionality in all telephone systems (Fix and mobile ones). What you hear when calling is send by the phone systems you are connected too (i. e. fix phone line of your provider central office systems). What makes your phone ringing is a command (teleco-protocol) sent by the system you are registered-in) So, we do not expect a ring to ring back sync any way.
2- To the previous fact, we should add the wake-up time, ringing tone search and play back as well as picture and info shown on display, call execution inner in the process on your JADE. You may minimize a bit these things, but I would say only a bit if you have the device always awake (battery waste) and your ringing tones are in the main memory.
3- if your phone does not give you radio problem, please do not upgrade it. You may run in problems you did not have before and it will void your warranty.
4- We can go further and add our ear and brain response time.
5- The time that comes for the call to go to diver destination or voice mail, counts from the moment that your phone is seized by your host public system and not from the moment the caller hear the first ring back tone.
I do not see a real problem as far as it does not go over two ring back tones.