The 3500/22M Transient Data Interface and the 3500/20 Rack Interface Module both relate to rack-level interface functions, but they should not be treated as the same ordering item.
3500/22M TDI
The 3500/22M combines rack interface functions with data collection capability for compatible software. It occupies the rack interface position adjacent to the power supplies.
3500/20 RIM
The 3500/20 belongs to an earlier rack interface generation. Legacy racks may still contain these modules.
Check the Installed Hardware
Before requesting a replacement, record the complete module number, rack configuration, and any I/O module information. A family-level description is not enough for a purchase decision.
Check the Document Revision
Manufacturer documentation can describe compatibility and replacement context. Use the current document associated with the exact product family, especially when software or rack communication functions matter.
Use the applicable manufacturer datasheet or manual for final configuration, wiring, installation, and engineering limits.