Apply some QOS on your 2811 to give VOIP priority and run some codec like G729 or something on your voip setup. G729 allows for voip streams of 8Kbps so it'll do wonders on your T1.
Good day! 2 cisco 2811 ISR from philippines and california. Both utilizing onboard VPN and voip features. 18 Cisco IP Phones & 20 workstations & 1 HP ML370 File server in branch (Philippines). Is this setup destined to be bugged with disconnection issues? Both site utilize T1. Is the 2811 not good enough if VPN and voip are turned on?