IRS Definition of Terms – you may find helpful (Part II) Codes
Collection Location Code (CLC) – The campus that will be responsible for the collection activities if needed.
Designated Payment Code (DPC) — A payment designated by the taxpayer for a type of tax.
Document Code (DOC Code) — The code which identifies the specific type of return or document that was filed or processed. The document code is the fourth and fifth digits of the DLN.
Extension Notice Code — A two-digit code assigned to Forms 2688/4868 identifying if the applications for extension of time to file returns were fully approved, granted 10–day approvals or denied, and the reason for the action taken.
Freeze Code — This could be on Master File or on AIMS
(a)AIMS—The code indicating that certain types of updates and closing actions will be prevented until the restriction (freeze code) is removed. Refer to Section 12
(b)Master File—A freeze places a taxpayer’s account in a condition which requires additional action before the account can be settled.
Master File Tax Code (MFT) — The MFT reduces the numerous types of tax to a two-digit code.
Status Codes – The two-digit alpha-numeric indicators that show the current status of a case.
Transaction Code — A three-digit code used to identify actions being taken to a taxpayer’s account. See Section 8.
Universal Location Code (ULC) – The processing campus associated with where the taxpayer resides.
(IRS Document 6209, TTT 8/17/21 & 8/24/21)