> For the complete documentation index, see [llms.txt](https://help.security.gallagher.com/knowledge-hub/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.security.gallagher.com/knowledge-hub/products/cc-hardware/readers/t-series/t-series-t20-user-guide-and-resolution.md).
# T20 Alarms terminal
Learn about T20 terminal capabilities, display resolution, user guidance, and Alarms Terminal limitations.
The Gallagher T20 Alarms Terminal (C300463 or C300464) is used for alarm and fence zone\
management. The terminal cannot be used for access, (i.e. it does not contain a smart card proximity\
reader or Bluetooth® low energy technology module
**Display:** Colour screen, native resolution **320x240 pixels**.
T20 Alarms Only Terminal
### Key Documents
T20 Alarms Terminal Install Note
T20 Alarms Terminal Datasheet
T20 End-User Guide
| Document | Description | Link |
| -------------------------------- | ----------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------ |
| T20 Alarms Terminal Install Note | Detailed information for installation. | [Download](https://media.gallagher.com/asset/c5de4cc3-8d64-499c-9371-0e424b9bfb6f/3E4495-Install-Note-T20-Alarms-Terminal.pdf) |
| T20 Alarms Terminal Datasheet | Overview and technical resource. | [Download](https://media.gallagher.com/asset/846362e7-9462-44fd-9433-679e1e2c9ba4/T20_Alarms_Terminal_Datasheet.pdf) |
| T2x Terminal User Guide | Information for the usage of the T2x terminals. | [Download](https://media.gallagher.com/asset/21c9e794-4411-4a54-aa29-35e49c41b075/3E3685-User-Guide-T2x-Terminal.pdf) |
The T20 user guide is located on the Install Media for each release of Command Centre under the Documentation folder. The T20 operation may change across firmware versions.
***
#### T20 Alarms Terminal limitations
> ⚠️ **The T20 Alarms Terminal cannot be assigned to a Gallagher Door.** It is designed exclusively for arming and disarming alarms and accessing system messages using a code (no card required). It does not support card-based access.
***
🔗 **Related**
* [T-Series](/knowledge-hub/products/cc-hardware/readers/t-series.md). T20 part numbers and accessories.
* [T-Series - T20 Firmware upgrade issues](/knowledge-hub/products/cc-hardware/readers/t-series/t-series-t20-firmware-upgrade-issues.md). Upgrading older T20 firmware.
---
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