Many businesses need ways to communicate through their business whether it be inside the store or out. Small business and even large corporations need ways to communicate with their employees and customers. They can range from multiple lines ranging from small systems to large branches. A business telephone can have multiple lines and can been accessed through other phones in that business. Business phone services can be defined in three categories: key systems, hybrid systems and private branch exchange.

Key systems were originally designed by the private branch exchange. It allowed the operator to access the calls manually that light up beside the number in the order the call came through. These are much like the private branch exchange system as they use a more direct calling system from a central office where the caller has to dial the number and is routed to the right operator.

Hybrid systems has a screen that shows the number and has different buttons that allows the operator to access the call and even transfer the caller by extentions. They are common in the financial businesses that usually require a central office for voicemail.

Private Branch Exchange was designed for bigger businesses that have a lot of calls. They differ of that of key systems because the operator is automatically chosen. The private branch exchange was chosen because of the savings as it reduced the cost of phone calls in and out and also its efficiency. Throughout the years this system has changed and is the most used through the country. They have designed this system to do four main things: make a connection between the telephones of the operator and caller, keep the connection as long as the operator and caller communicate, disconnect the connections when the users decide to hang up and also provide access to the accounts that the caller has with the business.

The business world has grown a lot throughout the years and continues to grow today.