PABX is a technology used by call centers and other large organizations that allows a single access number to provide several lines to outside callers while providing a range of external lines to internal callers or staff. PABX performs all the switching necessary for making internal calls between extensions within the organizations. It also allows provides a connection between extensions and external phone lines.
It typically offer a number of features to make communicating significantly more convenient. Key components include toggle, conference calls and picking up calls. Toggle is used to switch back and forth between multiple calls. With call pick-up you can answer a call to an unstaffed phone from your own phone. With conference call several subscribers can be included in a call and everybody can talk with all parties to the call. Other typical features of private automatic branch exchanges are callback, call waiting, call transfer and call forwarding.