General Overview

What is ZentriOS-S?

ZentriOS-S is a lightweight configurable operating system that provides a host microprocessor with a Bluetooth Low Energy (BLE) connection to any available BLE device. The S stands for Smart in Bluetooth Smart, an alternative name for BLE. ZentriOS-S is designed to substantially reduce design effort and aid time-to-market in applications that require BLE connectivity to other BLE capable devices.

ZentriOS-S is fully licensed for use on all BLE modules designed and manufactured by Zentri.

A host microprocessor communicates with ZentriOS via a serial interface. A host microcontroller can configure the module and stream data to and from connected Bluetooth devices. Application operation may be customized by setting individual configuration variables.

ZentriOS-S provides a powerful set of commands to enable host control, together with variables to enable host configuration. Beyond commands and variables, ZentriOS-S provides a rich feature set for wireless and peripheral command and control. ZentriOS-S can start and stop services and use GPIOs for control and indication.

Products and Features

ZentriOS-S is available as a range of products, each of which provides a subset of the full range of ZentriOS-S features. This allows a memory-constrained BLE device to run only the features you need to build your ZentriOS-S app. See Products.

For example, the commands for Peripheral scanning and connecting, allowing the ZentriOS device to take the Central role, are provided in the BLE Dual feature, available in the DUAL and TRUCONNECT products.

The variables for beacon advertising are provided in the BLE Beacons feature, available in the BEACON product.

Supporting features and products are listed for each command and variable.

To change the ZentriOS-S product on your device, see Update and Recovery.

Serial Interface

ZentriOS-S provides one of the easiest to use and flexible serial BLE interfaces in the industry. The ZentriOS-S serial interface provides UART support, different serial communications modes including command mode and stream mode, and is easily configured for use by humans and machines.

See Serial Interface.

Bluetooth Low Energy

ZentriOS-S provides an easy-to-use serial API allowing you to focus your efforts on application development, rather than the time-consuming complexity and interoperability issues associated with the development of a wireless network stack.

ZentriOS-S supports operating modules in Central and Peripheral roles.

See Commands and Variables.


Various peripheral APIs are available to provide access to general purpose IO function including pulse width modulators (PWM), ADCs, DACs, and standard I/O.

See Peripherals.

Beacons and Advertising

ZentriOS-S supports advertising with specific beacon types such as iBeacon, as well as providing a generic beacon type that can be used to create any beacon format.

See Beacons and Advertising.


ZentriOS-S supports Security Mode 1 (encryption) with its first three levels. See Security.