# Digital Signage

This guide describes how to use the API to display information on digital screens in buildings.

## Sections

- [Activation level](/guides/cases/digital-signage/activation-level) — Per real estate or per organization.
- [Access](/guides/cases/digital-signage/access) — Read-only entities for display.


## Entity relationships

You can start from address (gate/door), real estate, or building and traverse to spaces and tenants.

**Structures and spaces:**


```mermaid
flowchart TB
  RE[RealEstate]
  B[Building]
  A[Address]
  APT[Apartment]
  IP[IndustrialPremises]
  PS[ParkingSpot]
  BRF[BrfApartment]
  CA[CommonArea]
  COM[Community]
  REG[Region]

  B --> RE
  APT --> B
  IP --> B
  PS --> B
  BRF --> B
  CA --> B
  B --> A
  APT --> A
  IP --> A
  PS --> A
  BRF --> A
  CA --> A
  COM --> RE
  REG --> COM
```

**Tenants and contracts:**


```mermaid
flowchart TB
  APT[Apartment]
  AC[ApartmentContract]
  T[Tenant]
  ST[SubTenant]
  SCC[SubtenantContractConnection]

  AC --> APT
  T --> APT
  ST --> APT
  SCC --> AC
  SCC --> ST
```