Step 1 – Identify the Appropriate Transaction Code
Transaction codes (T-codes) are three-digit numbers that determine the accounting impact of each transaction entered in USAS. Each T-code is defined on the following screens:
- Transaction Code Decision Profile (28A)
- Transaction Code Options Profile (28B)
- Transaction Code Description Profile (28C)
The T-Code Reference Guide 
sorts all the USAS transaction codes into manageable lists to assist
you in identifying the correct code for your transaction.