TADIG

TADIG (Transferred Account Data Interchange Group) is the GSMA working group that defined how mobile operators exchange roaming usage and billing data. The name also refers to two things that came out of its work: TADIG codes, the 5-character identifiers for operators in roaming billing, and TADIG testing, which checks that roaming usage is recorded and billed correctly between partners.

TADIG codes

A TADIG code has five characters: a three-letter country code — usually the ISO 3166-1 alpha-3 code — followed by a two-character operator identifier. Codes are registered with the GSMA and serve as primary identifiers in roaming file names and contents under the naming rules in GSMA TD.13. An operator may hold more than one TADIG code, and each code corresponds to networks identified by MCC/MNC.

TAP, RAP and BCE

When a subscriber roams, the visited network records the usage and sends it to the home network for wholesale settlement:

Format	Purpose
TAP (Transferred Account Procedure)	Call, SMS and data records sent from the visited to the home network; the TAP3 format is specified in TD.57
RAP (Returned Account Procedure)	Records the home network rejects and returns; specified in TD.32
BCE (Billing and Charging Evolution)	A newer, simpler settlement framework. TAP is not being extended to cover 5G SA, NB-IoT or LTE-M, so these rely on BCE

TADIG testing

Before roaming launches commercially, partners generate and exchange test usage files to confirm that the visited network records usage correctly — right IMSI, timestamps, durations, volumes and operator codes — and that the home network can process the files. TADIG testing usually follows IREG testing: IREG proves the service works, TADIG proves it is billed correctly. The test calls and sessions made during IREG Stage 3 commonly produce the records that TADIG testing checks.

Why it matters for testing

Billing records are only as trustworthy as the usage behind them. Controlled, known usage — a call of a set length, a data session of a measured volume — makes reconciliation possible. Real calls, SMS and data sessions run on live networks, such as those SimCheck.ai executes, give roaming teams known events to compare against settlement records — see IREG vs TADIG testing.