In the not-too-distant past, only call center agents at dedicated contact centers used CTI. While these agents are still heavy users of CTI, as the software has become more accessible, itâs also become popular with all kinds of businesses. IT and customer service teams have particularly become prominent users of CTI. Inbound and outbound call centers can benefit from CTI, but the tools they use will differ. Outbound call centers can take advantage of the advanced calling tools, while inbound call centers will implement IVR.