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BLE           UWB           IoT

RFID stands for Radio Frequency Identification. ‘Passive’ means the RFID tag does not contain a battery and therefore cannot broadcast its identity on a regular basis. It must be ‘energised’ by a reader antenna, typically in close proximity, before it can communicate its stored information, which is typically a simple ID number. Since there are no batteries the cost of a passive tags is low, hence the growing adoption in retail.

Main Types of Passive RFID

There three main types are Low Frequency (LF), High Frequency (HF) and Ultra High Frequency (UHF). LF is the oldest and simplest, still popular in access control and animal tracking where it is least affected by liquids and body tissue. HF is used extensively in proximity cards for access control, and also payment cards. It was widely adopted by libraries for asset tracking but limitations on read range and reading large volumes of tags at the same time restricted market growth. Passive UHF is the newest and most widely used technology for item tracking. It has globally adopted open standards, meaning equipment and tags purchased from different manufacturers is inter-operable. Whilst still inexpensive, tags can be read over greater distances and in high volume at the same time. This is the primary technology used by Codegate in our asset tracking applications.


UHF RFID readers typically connect to a host computer using ethernet, or if it’s a handheld reader, over WiFi or a cell phone network. The data rates can be high, so good software is essential to filter and control the information down to what is relevant to the application. Codegate provides PC based software which manages data from any number of remote readers, but also embeds software onto readers themselves. This means readers can continue to operate on a ‘store and forward’ basis even when the network is down, see for example Codegate’s eVantage software.

Integration with Lime

Codegate's eVantage software can be embedded into passive UHF RFID readers from Zebra and Keonn so they work seamlessly with our Lime asset tracking middleware.

Lime Asset Inventory mobile app can be used to conduct manual inventories on assets identified with HF or UHF passive RFID tags. Featuring a Geiger counter style search utility it's also easier to locate missing items.


Passive UHF RFID can also be used in for Real Time Location (RTLS). Codegate has collaborated with RF Controls to fully integrate their passive UHF RTLS scanning system with our Lime middleware.


Uses for HF include payments, access control and in this case identification, using NFC wristbands to record individual scores in this arena based game designed to test strategy, speed, agility, awareness and bravery.


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More about eVantage Read Station Solution

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Find out about our asset tracking middleware

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Read about BLE and Active RFID technology

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