I have 2 sites, one site is a 3640 to PSTN via FXO, the other site is a 5300 to a switch. I use Connetion PLAR to connect 2 sites via internet. The IOS in 3640 is IOS (tm) 3600 Software (C3640-JS-M), Version 12.2(31), RELEASE SOFTWARE (fc2), in 5300...