A PBX provider (Private Branch Exchange provider) is responsible for offering businesses a communication system that manages internal phone systems, call routing, voicemail, and more, often integrating with traditional telephone lines, mobile devices, and VoIP (Voice over Internet Protocol) services. These systems allow companies to manage their internal communication more efficiently while providing features like call forwarding, conference calling, and auto-attendant services.

On the other hand, an FXO VoIP gateway is a device that connects traditional telephone lines (POTS or Plain Old Telephone Service) to a VoIP network. "FXO" stands for Foreign Exchange Office, and it refers to the interface used to connect the VoIP gateway to the public telephone network.

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