9.12 Conclusion

---

Even though the basic functions of CSU-DSUs have not changed in almost 30 years, they are critical to carriers and customers alike. Acting as a protective barrier for the carrier’s network and an interface or signal converter for the customer, a CSU-DSU also provides a variety of functions that ensure WAN links run properly.

Improvements in the underlying technology have enabled CSU-DSUs to evolve from interface devices that sat passively on the network to “intelligent” devices with sophisticated network management features, innovative diagnostic capabilities, and higher levels of functionality that enable users to take full advantage of new digital services. While CSU-DSUs are available as standalone units, they are also available as add-in modules for channel banks, multiplexers, and routers.

---