The Original BAILEY 6637517A1 System Module Spare is a circuit-board assembly used in the Bailey INFI 90® distributed control system. Based on available evidence, it is a miscellaneous (MISC-series) interface/keyboard circuit card belonging to the Bailey 6637xxx board family.
Key Features
- Circuit-board assembly for the Bailey INFI 90® DCS product family
- Associated with the Bailey “660-MISC” miscellaneous board series
- Likely an interface / keyboard-interface class card within the INFI 90 operator or cabinet subsystem
- Standard INFI 90 module form factor (one-slot plug-in module)
- Field-replaceable board, typically used in power, process, and infrastructure plants with legacy INFI 90 DCS
Technical Specifications
- Type Designation: 6637517A1
- Product Type: INFI 90 system circuit board
- System: Bailey INFI 90® DCS
- Board Family: Bailey 6637xxx
- Mounting: One slot in a standard INFI 90 module mounting unit
- Dimensions / Weight: approx. 3.7 × 31.7 × 17.8 cm, approx. 0.1–0.24 kg
- Origin: United States
Installation Notes
- Verify the board’s actual function and pinout against the INFI 90 cabinet drawing before installation — do not rely on conflicting market listings.
- De-energize the INFI 90 power system before inserting or removing the board from its slot.
- If the board belongs to the operator console subsystem, confirm the cable routing to the keyboard/interface panel per the original console manual.
- After installation, verify module status via the INFI 90 diagnostics / operator station before returning the loop to service.
Common Questions
Is 660-MISC-3311 the same part? Multiple different Bailey part numbers (6637517A1, 6637804CI, 6637849E1, IMDS001) have been associated with “660-MISC-3311” by different dealers, so the 660-MISC-3311 reference itself is unreliable as a unique identifier and should not be used alone for ordering.
Can this board be ordered as a “digital input module”? Only if confirmed by documentation. The “16-channel digital input” description appears in low-credibility listings only and conflicts with other listings; ordering it as a DI module without verification risks receiving a wrong part.













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