Telecom For Dummies

The Channel Service Unit (CSU, pronounced see-ess-you) is a little device about the size of a cigar box that’s used on dedicated circuits. It is the first piece of hardware you need to make your dedicated circuit work, and its daily job is boosting the signal coming in from your carrier. The CSU is also the first piece of hardware used to validate the continuity on a dedicated circuit.

 Tip  If you want to impress a technician without sounding obvious, say, “Wow, you can test to my CSU without any problem? That’s great! I’ll call my hardware vendor right now to fix my phone system and then cut out for lunch.”