Despite the use of the internet being in great expansion, the use of fixed and mobile telephony is still one of the most used means. In companies this use is still expressive and counts on a PABX, equipment to manage trunk lines and ip´s or analogical extensions. Today's PBXs are devices that are part of the network, allowing their configuration to be done even remotely, offering cost savings through automatic line selections, built-in call identification and answering. Everything you need in a single device. We at Vercan, as an IT management company, carried out a study to size the correct equipment for each type of company need, configuring access routes and managing connections.