With the traditional PBX, one extension can keep only one call on wait, while the other call is in progress. More incoming calls cannot be entertained.

Your business might survive this sometimes. But this situation can be the business-killer during the rush hours. When the call flow is at its peak, every missed and untracked call is a customer that you are losing. Thus, the traditional PBX services are likely to cost you a huge loss; unless you hire more operators and install additional extensions for them. That itself is a very costly affair. Isn’t?