This document describes the rules that govern the mechanized transmission of data between entities ordering and providing access services. This document supports the Access Service Ordering Guidelines Industry Support Interface (ASR Document) which describes the industry agreed upon guidelines for the ordering of access services. PLEASE NOTE: The ATIS Ordering and Billing Forum (OBF) Access Service Ordering (ASO) Subcommittee recently identified an error(s) in the publication. The REFNUM field was removed from the F51B "PERMANENT VIRTUAL CONNECTION (CIRCUIT LEVEL)" replaced with RESERVED FOR HEADER DATA in Version 51.1. The ACCESS_CKT and ACCESS_ORD fields were removed from the N "Confirmation Notice (CN)" record and correctly added to the R20A "Associated Circuit Level Data" record in Version 51.1.