The following is the evolution of communication between customers and enterprises, related technologies and human resource requirements for this change.

Original Call center
Customers began to call the company since the phone was invented, and the company hired more employees to answer the phone in order to receive more calls. This led to the birth of the call center.
To effectively manage call centers and provide productivity, we introduce new technologies such as automatic call distribution (ACD) queuing incoming calls and fair routing among agents; interactive voice response (IVR) interactive access to information from calling parties and providing autonomous service capabilities; computer telephony integration (CTI) allow enterprise software to control processes and promote screen pop-ups through customer information; free dialing, free dialing for customer answers; call recording to ensure communication quality and more.
The mechanism for call distribution is very simple, mainly based on agent availability. When an agent is in a ready state and no other call is processed, the agent is considered to be able to make a call. However, if the agent is processing the call, no new calls will be assigned to the agents. The statistics of the agents are also defined and calculated according to this method. For example, the agent rate is to calculate the time that the agent spends outside the total logon hours.

SMS and Email interaction
With the development of the Internet and its infiltration into various fields of human life, new communication services such as e-mail and mobile SDK have emerged. It is not surprising that they can be the focal point for innovation, but in most cases this adoption is not procedurally consistent with call routing in call center environments. Initially, agents handle these multichannel interactions through one medium or switch their availability from one channel to another on a regular basis throughout the day, or the agent manually receives e-mail or chat from an ordinary queue. Automated “mixed” multi-channel interactions face many technical challenges at this time
Initially, e-mail messages and chat sessions are processed and routed to agents like voice calls. This leads to unexpected problems: when an agent who assigns voice phones and e-mail messages receives an e-mail and starts processing the business, it cannot receive new voice calls because the router considers the business to be busy. It is often desirable to assign voice calls to agents that are using email because typical voice calls can not or do not wait, and email processing may be postponed for some time; however, this was not possible at the time.
In addition, an agent who works in a single chat session cannot work in another chat session while waiting for the first customer to finish typing their response. Secondly, the router treats the agents as busy interactions that cannot be interrupted by another interaction. A well-trained agent can work three or more chat sessions at the same time, so continuous processing of chat interactions leads to loss of productivity. It is very clear that a more sophisticated method or technique is needed to assign the agents to the same time or multi-channel interaction. Also, some improvements to the agents’ statistics are entirely needed. With the introduction of network form, fax and SMS, these problems become more urgent and exaggerated.

Multichannel contact center
The proliferation of communication channels in the contact center environment has led to unify channels and separate interaction logic from channel-specific details. This led to the new concept of a full channel contact center. It is assumed that such a contact center would have the means to interact easily with many channels, allowing for example seamless switching from one channel to another, while maintaining the communication context.
The concept of a channel-wide focal point requires the establishment of a solid technical base to deal with multi-channel interactions, including routing and integrated reporting. </p>

Rich Contact Experience
The boom in mobile technology over the past few years has provided new opportunities for the development of contact center technology.
Mobile technology allows new rich contacts to be created: complete communication channels between customers and contact centers that can host any interaction between different media types. For example, customers can communicate with the auto insurance contact center through their mobile devices about the car accident they are involved in and the customer explains the situation to the agent through the Voice channel. At some point in time, customers may take photos of damaged cars and send them as picture messages in the form of a call.
In a rich connection, customers can use any available channel, such as chat, voice, messaging and video parallelism or any number of times in any order. Emerging and future channels will also be incorporated into rich contacts without changing the contact processing logic.
This freedom of use by the media increases the productivity of clients and agents in the transaction. However, chat and voice transactions with different customers simultaneously give the contact center representatives a different burden of chatting and voice calls to the same customer, and the existing full channel system will not be able to take advantage of this increase and not meet the evolving customer base.

In the WCC, we advocate a new rich contact experience model, and believe that the links between customers and contact centers become richer and more complex which greatly improve customer service quality. To do this, we have introduced a new approach to arrange the work of the agents and assign them multiple channels of interaction to improve their productivity and utilization.