From CT Wiki
In case you want to use EVO from your laptop and a PolyCom device, perform the following steps:
Do NOT turn off the gatekeeper on the polycom, otherwise it won't work! Connect with your laptop to EVO and enter the meeting. Choose Call > H.323 Fill in a display name. Fill in H.323 address field the IP address of the PolyCom device use want to use. It will call the PolyCom and get connected.
SURFnet: 220.127.116.11 ESnet: specify, IP 18.104.22.168, E.164 extensions 200447, 202567 of 202568. EVO: like ESnet (?) Direct: off
General network addresses (usually not needed, check in case of problems):
DNS: 22.214.171.124 126.96.36.199 Gateway: 188.8.131.52 Subnet: 255.255.255.0