Takes too much time to stablish a call

Hi guys, i need some help here. I have this model VS-GW1600 GSM Series and i have a asterisk server running with openvox to make calls. I use around 8 SIM cards to stablish a call.
The problem starts when i try to make a call, normally, when i use a sim card on my phone without the openvox, it takes 1 second or 2 maximun to stablish to start to ring. Now, when i use this SIM cards in my openvox, i need to wait 10 seconds (average) to hear the ring. I have several clients that depends of this sim cards to make a call from their centrals.
Here is a snapshot of my openvox web interface, i hope you can help me here.

This is the general system status of my sim cards




And this is the detail of one of them.


Thanks a lot since now !

Hi, I saw the PDD is 5 or 6 seconds, that should be normally, did you try to use a softphone register to the gateway to test? and what's your firmware version?

Yes, i have tried that and that's when i noticed the retard on the call. Dude, how can i edit the post Dialing delay? I need instead of 5 or 6 seconds, just 1 or 2 .
This is my system information :

I saw the signal of your gateway is a little low, please move it to a place with better signal.

I 'll try that , but can you let me know if there is a method to edit that PDD. It turns me crazy

sorry, we can not edit this value, it related to the gsm network, if the gsm network is better, this value should decrease.