# Can on-premise Exchange calendars connect with Free/Busy Calendar Access Mode?

Free/Busy Calendar Access Mode is only available for Google and Microsoft 365 calendars. It isn't available for on-premise Exchange.

On-premise Exchange calendars connect with Read-Write access, either through [Individual Connect](https://docs.cronofy.com/connect/calendar-users/connecting-to-exchange/index.md) or [Enterprise Connect](https://docs.cronofy.com/connect/calendar-admins/enterprise-connect-office365-exchange/index.md).

If an organization's policies only allow Cronofy to see free/busy information, its Exchange admin can [limit the Enterprise Connect service account to free/busy access](https://docs.cronofy.com/connect/calendar-admins/enterprise-connect-office365-exchange/free-busy-access/index.md). Your application then requests the `free_busy` scope, as described in [Free/Busy only](https://docs.cronofy.com/developers/calendar-and-availability/access-modes/free-busy/index.md).

These connections are read-only, so the [Create or Update Event](https://docs.cronofy.com/api-reference/calendar-control/calendar-events/upsert-event/index.md) endpoint can't be used with them. Instead, you can send the user a [Smart Invite](https://docs.cronofy.com/developers/calendar-and-availability/calendar-events/smart-invites/index.md).


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