> 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-frequently-asked-questions-fa.md). # T-Series reader common questions Find answers about reader revisions, T20 features, firmware upgrades, cards, and Mobile Credentials. ### Why are there multiple revisions of T10, T11, and T12 readers? Rev 0 for the T10, T11, and T12 readers was the very first release and only went out to a limited number of sites - it did not have any HBUS communications built into them even though they had the green, brown, and orange wires and only communicated via Cardax IV format. They can be identified by looking at the back of the reader and noting that they have no Rev identifier on the label, also they will have only the Gallagher labelling on the front (no diamond or "125" symbol). Rev 1 is the latest release for the T10, T11, and T12 readers and have the HBUS functionality. *** ### What do the different identifiers on the front of readers mean?
PictureDescriptionApplicable Models
MIFARE onlyT10, T11, T12, T20 & T30
Multi Tech (MIFARE, 125, BLE)T11, T12, T15, T20 & T30
PIV High SecurityT10, T11, T15, T20 & T21
Multi Tech (Old identifier)T11, T12, T20
*** ### Why does the T20 Alarms Only Terminal not get assigned to a door? The T20 Alarms Only Terminal is designed to be an alarms terminal for arming and disarming alarms, accessing system messages without the use of a card (code-only access). It cannot be assigned to a Gallagher Door. *** ### Why can I not upgrade an old T20 reader? This is most likely because the reader has been changed from a CardaxIV connection to an HBUS connection. The original release of T20 firmware (1.x) cannot directly upgrade to 4.x or higher. The reader must be upgraded to 3.x first by connecting the T20 to a system running CC version 7.30 to 7.60 and upgrading the firmware there first. *** ### Why do Gallagher-encoded cards beep once at a reader? This is likely because the site has a **SSK (Site Specific Key)** for its DESFire cards, and when the cards were sent to Gallagher for encoding, the SSK was not supplied. This can be resolved without returning the cards to Gallagher, but will require guidance from Technical Support. *** ### Why can I not assign one reader to two doors with Mobile Credentials? This will work with card technologies, but because the Mobile Credential is a certificate, the credential cannot be verified on two doors at the same time. *** ### How to add custom images to the terminal? If different per reader: Navigate to the reader properties, then the audio-visual tab. If the same across the site: Navigate to the Server properties, then HBUS Terminal Defaults 1 tab Go to the Screen section - different images can be applied to idle, access granted and access denied. Browse and/or preview using the buttons. * When browsing for an image, only **.png**, **.jpg** and **.jpeg** files display. * The image size must be 320 x 240 pixels ### How to add custom sounds to the terminal? If different per reader: Navigate to the reader properties, then the audio-visual tab. If the same across the site: Navigate to the Server properties, then HBUS Terminal Defaults 1 tab. Go to the Tones section - different tones can be applied to Access Granted and Denied. Browse and/or preview using the buttons. * When browsing for a sound file, only **.wav** and **.mp3** files display. * The sound file will play for a maximum of 3 seconds, and will be no bigger than 100 kilobytes. *** 🔗 **Related** * [T-Series - Non HBUS compatible](/knowledge-hub/products/cc-hardware/readers/t-series/t-series-non-hbus-compatible.md). Identifying Rev 0 versus Rev 1 readers. * [T-Series - T20 Firmware upgrade issues](/knowledge-hub/products/cc-hardware/readers/t-series/t-series-t20-firmware-upgrade-issues.md). The 1.x to 4.x upgrade path. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://help.security.gallagher.com/knowledge-hub/products/cc-hardware/readers/t-series/t-series-frequently-asked-questions-fa.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.