> ## Documentation Index > Fetch the complete documentation index at: https://seam-feat-mintlify-migration-iteration.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Access Control System Resources > Learn about the Seam resources that you use to manage your ACS. The Seam ACS schema consists of a series of resources. These resources interact intuitively, enabling you to manage your ACS in a logical, efficient manner. Seam's universal API provides the flexibility to manage a variety of [ACSs](./understanding-access-control-system-differences), each of which may have manufacturer-specific differences. For details about your ACS, see the corresponding [system integration guide](/device-and-system-integration-guides#access-control-systems). The following diagram shows an example of one ACS, including the ACS resources and the relationships between them:

Seam's ACS resources provide the flexibility to manage your ACS intuitively, regardless of the differences between various ACS manufacturers.

The following table provides a brief description of each of the Seam ACS resources:

ACS Resource	Description
`acs\_system`	The top-level object. Represents one or more buildings, residential locations, or other sites that you manage using this ACS. For more information, see{' '} Retrieving ACS System Details .
`acs\_user`	The set of users who access the entrances. If you manage multiple ACSs and need to grant the same user access to{' '} entrances in multiple ACSs, you can also use Seam{' '} user identities . With user identities, you can link an application user in your own system to one or more Seam ACS users. For more information, see{' '} Managing ACS Users .
`acs\_access\_group`	Some ACSs use access groups as an efficient way to grant sets of scheduled entrance access to one or more users. For more information, see{' '} Assigning ACS Users to Access Groups .
`acs\_credential`	A digital means that authorizes a user to access one or more entrances at specific days and times. Examples of credentials include RFID cards, mobile keys, and PIN codes. For more information, see{' '} Managing Credentials.
`acs\_entrance`	The set of entrances, doors, or zones that you want to manage. You identify each entrance by the corresponding lock object. For more information, see{' '} Retrieving Entrance Details .

You configure the access schedules for your ACS users either through access groups or credentials, depending on your specific ACS. There is no separate schedule resource in the Seam API.