User manuals are sorted by product serial number and model codes. The first 4 digits of the serial number represent the manufacture date (YYMM) eg, 2203-XXXX = March 2022 build date.
CURRENT Models: TDB-1-4E, TDB-2-4E, TDB-4-4E
January 2024 - current (2401 - current)
Models: TDB-1, TDB-3
October 2023 - December 2023 (2310 - 2312)