Answer first
Core rule
Answer first: the 11-character entry number contains a three-character filer code, a seven-digit filer-assigned sequence with leading zeros preserved, and one numeric check digit computed from the preceding ten characters. The four-character port uses DDPP format, while the two-digit entry type is a separate field whose first and second digits identify the general category and specific processing type. The October 2026 CBLE designates ACE Entry Summary Instructions Version 2.4a; a newer operational CATAIR may inform live filing but must not silently replace the exam source.
Authority and lookup route
Locate the rule before returning to the facts. Links point to government or official publications.
Reference lookup task
Find the length, source, and relationship of Entry Number, District/Port of Entry, Entry Type, and the check-digit formula.
Route: Read the Header Level Information and Check Digit Computation Formula in ACE Entry Summary Instructions 2.4a.
Worked example
Parse entry number ABC00481236 with port 2704 and entry type 01, then verify the check digit.
- 1Parse ABC as the filer code, 0048123 as the seven-digit assigned sequence, and 6 as the check digit.
- 2Use the ACE 2.4a filer-code conversion table (A=1, B=2, C=3 for these letters) to convert ABC0048123 to numeric base 1230048123; the adjusted even-position sum is 20 and the odd-position sum is 14.
- 3The base-value ones digit is 4, so 10 minus 4 produces check digit 6.
- 4Read 2704 as the separate DDPP port and 01 as the separate two-digit entry type.
Conclusion: ABC00481236 is structurally and computationally valid for this example; port 2704 and entry type 01 are separate header fields.
Common traps
- Using a letter such as X in the numeric check-digit position.
- Dropping leading zeros from the seven-digit assigned sequence.
- Treating the port or entry type as part of the 11-character entry number.
- Replacing exam Version 2.4a with a newer operational guide without an explicit version decision.