CID (Company ID)
NENA Company Identifiers (also known as Company IDs or CIDs) allow 9-1-1 centers to quickly identify the telephone company or access infrastructure provider responsible for a particular telephone number.
Access Infrastructure Provider ID
A 3-5 character identifier that distinguishes the entity providing voice service (e.g., Wireline, Wireless, VoIP, PBX, etc.) to the end user. The company identifier registry is maintained by NENA in a nationally accessible database.
Also known as Company Identifier (ID) 1 or CID 1
Data Provider Company ID
A 3-5 character identifier that distinguishes the source of the ALI record information (e.g., service provider/reseller/private switch owner).
Also known as Company Identifier (ID) 2 or CID 2
More information on NENA Company Identifier Program: http://companyid.nena.org/