An Integrated Services Digital Exchange (ISDX) is a stored program control (SPC) type of private automatic branch exchange (PABX), and provides efficient, reliable control of fully integrated voice, text and data communications. Its modular design enables the system to be easily upgraded to incorporate new hardware and software. The system allows evolution of private networks, either on a single site, or as a sophisticated corporate network.

The ISDX family comprises four sizes of exchange; large (ISDX-L), small (ISDX-S), mini (ISDX-MN) and an extended traffic version of the large exchange, (ISDX-T).