What is a Registered Identifier?

A terminal or terminal emulation software which is linked to a UK acquirer and accepts card payments must have a unique terminal identifier (TID). The TID ensures the uniqueness of the transaction source for audit purposes. The RID system enables a terminal manufacturer to uniquely identify 10,000 units on each RID.

The Terminal Identifier (TID) consists of two parts:

• Registered Identifier (RID) — Four digits, issued by the Registration Authority and entered on the Register.
• Unit Identifier (UID) — Four digits assigned by the holder of the Registered Identifier making the identification of an individual terminal unique.

APACS is the Registration Authority responsible for maintaining the UK register of four-digit Registered Identifiers (RIDs) used by point-of-sale terminal manufacturers for the construction of Terminal Identification numbers (TIDs).