Common Language Information Services encompasses several products that are in general use by the global telecommunications industry through license agreements.
Common Language products combine numerics and mnemonics to establish naming conventions that telecommunication companies use to exchange critical information via Operations Support Systems and other interface mechanisms.
[1] They identify items as large as a building, as small as a single board in a digital switching machine and as complex as a customer circuit.
Common Language code sets are recognized by industry standards bodies and organizations, including ATIS,[3] ANSI,[4] IETF,[5] and ETSI.
CLEI codes may be acquired by telecommunications equipment manufacturers and assigned to devices before they are sold to a licensed service provider.