I've never heard of it either. I googled it and came up with this:
A little known credit check that telecom and utility companies do among themselves may have a significant impact on your ability to receive services and whether or not a deposit will be required. The National Consumer Telecom & Utilities Exchange (NCTUE) is a member-owned database managed by Equifax. According to the NCTUE website, the database exchanges information on new connects and defaulted and/or fraudulent accounts among members. It also gives the companies access to consumers' current contact information on defaulted consumers, and provides treatment and collection strategies for alleged unpaid bills.
I'm guessing it is some sort of score they provide.