In the early days a company with a manual telephone switchboard or switchboard was operated by a person plugging cables into sockets. This was known as a private Manual Branch Exchange or PMBX). These were replaced by electromechanical and finally PABX electronic switching systems also called Private Automatic Branch exchange. PMBX are rare these days, and the term PABX and PBX are widely used. The term PBX is still more widely used. PBX systems select their own lines randomly to make outgoing calls. These lines are referred to as trunk lines.
A PABX connects all the business’s instruments separately to the public telephone network PSTN or ISDN. A PBX switchboard assists in that every internal call made is routed through the PABX (central switch).
In the IP Telephone System, there are several advantages businesses can benefit. Some of the standard features are IVR, Voice Mail, Call Recording, Voice Mail to Email, Mobility Users, Call Queue, Conference call bridge, Telephone CRM Integration and Remote office connectivity. With IVR and call queue you can handle more calls with few staff on board. The Voicemail, Voicemail to email and Mobility options make sure you never miss customer reach even out of the office. Conference call bridge, The Telephone CRM Integration, and Remote office connectivity provide higher business productivity.