U-Net is Wireless communication standard largely based on IEEE 802.15.4 standard which is an IEEE technical specification defining the operation of low-rate wireless personal area networks (LR-WPANs). It specifies the physical layer and media access control for LR-WPANs, and is maintained by the IEEE 802.15 working group, which defined the standard since 2003. It is the basis for the Zigbee, ISA100.11a,, 6LoWPAN, Thread and SNAP specifications, each of which further extends the standard by developing the upper layers.

IEEE802.15.4 intends to offer the fundamental lower network layers of a type of wireless personal area network (WPAN) which focuses on low-cost, low-speed ubiquitous communication between devices. It can be contrasted with other approaches, such as Wi-Fi, which offer more bandwidth and requires more power. The emphasis is on very low cost communication of nearby devices with little to no underlying infrastructure, intending to exploit this to lower power consumption even more.

With IEEE802.15.4 as its underlying layers, U-Net offer key features such as:

  • Two-way communication
  • Low power consumption for battery devices
  • Reliable connection; periodic check, transmission retries and collision avoidance per IEEE802.15.4 defined CSMA/CA
  • Range up to 250m in open site
  • Secure communication using Advanced Encryption Standard (AES)


2005 : U-Net 1.0 released by Everspring. This protocol is an evolution from previous Sub-GHz protocols used by Everspring in home automation/alarm products sold in the European market for nearly 10 years. Alarm products adopting U-net were released.

2007 : U-Net 2.0 released. Taking advantage of U-net’s fast transmission, this update adds bulk data transfer for connection to PC and gateways for large message packets. It also added enhanced low power mode for extended battery life for sensor devices. More data-intensive automation devices such as metering plugs and environment sensors were added to coincide with release. With the advent of smartphone and cloud servers, this version also formed the backbone of new generation smart home products, transferring large data rapidly between controller and gateway.

2012 : U-Net 3.0 released, among its new features include support for periodic auto-report by devices and automatic pairing when first power (‘Auto-binding’) to facilitate installation. This version was used on projects for telecom operators throughout Europe, and forms the largest market adoption of U-net to date. Significant minor updates were later added based on market feedback and field tests.

2015 : U-Net 4.0 released, major enhancements include AES-128 encryption, support for antenna diversity and sensor software upgrade by OTA (Over-The-Air). These enhancements add toughness and robustness to the protocol for special IoT application in rugged wireless environments. Successful deployments include site monitoring of LTE base station projects in the Middle East and non-invasive AC mains power metering in the French market.


More than 1.5 million products have been shipped adopting U-net technology.