Salto XS4 Controller I/O Expansion.
The input/output expansion unit extends the CU4200 with eight relay outputs and four inputs, for control points that need to switch more than the base controller alone. It is specified alongside the CU4200 when a single access point drives multiple relays or reads multiple inputs.
Where this model fits
- Control points driving multiple relays
- Integrations needing extra inputs
- Larger or more complex access points
Parent product line
XS4 Controller I/O Expansion is a configuration of the Salto Controller product line. See the parent line page for the full credential stack, PMS integration list, and brand-standard notes that apply across every Salto Controller configuration.
How this model is configured
Every Salto lock is composed to your doors during scoping: finish, mortise and function type, credential technology (BLE, NFC, RFID, with mag-stripe or PIN fallback where needed), and handing. RevKey confirms each selection at the site survey and configures the final composed part number with you, so the lock that ships matches your door prep and brand standard.
Datasheets & documents
Where XS4 Controller I/O Expansion fits, and where it doesn’t
Best for
- Driving wall and long-distance readers (two readers per CU4200)
- Releasing elevators, gates, turnstiles, and amenity doors
- Growing control points with the I/O expansion or BLUEnet door controller
Not ideal for
- Self-contained electronic locks that need no separate controller
- Sizing by room count rather than by non-door access points
- Outdoor mounting without appropriate enclosure
Sourced from SALTO CU4000 Door Controller product page. Reviewed 2026-06-26 by RevKey.
Next step: scope a XS4 Controller I/O Expansion install
Tell us about your property and we will come back with a real scope for a XS4 Controller I/O Expansion install, including configuration selections, phasing, and brand-standard compliance review.