Which statement about Avaya Messaging integration with a third party PBX is true?

Avaya Messaging is designed to be flexible and interoperable with various telephony systems. It supports integration with third-party PBXs as long as they use standard communication protocols such as SIP (Session Initiation Protocol), H.323, or ISDN (Integrated Services Digital Network) links. These protocols are widely adopted in the industry, allowing Avaya Messaging to work seamlessly with a diverse range of PBX systems, ensuring broad compatibility and integration options for businesses.

References: The information about Avaya Messaging’s capability to integrate with any PBX using standard protocols is supported by Avaya’s technical documentation and integration manuals123.