Calls go to voicemail after inactivity. NAT Keep Alive

[bglotz]

I'm using MagicJack behind two routers. After about 15 minites of inactivity all incoming calls go directly to voicemail. I have read some other topics and it sound like I need to change my "NAT Keep Alive" setting. My question is where do I change this setting? Is it withinh the MagicJack or one of the routers?

Thanks,

Ben