I couldn’t find a verified reference to an in public product databases, manufacturer listings, or common industrial catalogs. It’s possible this is:
Some very early units (pre-1975) used a three-digit year code (e.g., 973 for 1973). If you see only four digits without a dash, try breaking it as YYMM. Adeko 22 Serial Number
The "22" in Adeko 22 refers to a specific release year (2022) or version number, signifying a suite of updated features, typically including: I couldn’t find a verified reference to an
If you own one of these instruments, proper documentation preserves its history for future collectors: signifying a suite of updated features