According to the Cisco Unified Contact Center Express Design Guide, Release 8.0(1), the maximum number of CTI ports that can be supported by a Cisco Unified Contact Center Express 8.0 Standard deployment is 300. This is the same as the maximum number of IVR ports that can be supported by the Standard deployment. The CTI ports are used to route calls to agents or to play prompts and collect caller input. The number of CTI ports depends on the number of concurrent calls that the system needs to handle and the call flow design. The Standard deployment supports up to 150 agents and 300 IVR ports or CTI ports. References := Cisco Unified Contact Center Express Design Guide, Release 8.0(1), page 2-7.