Integration Guide
SMK900 Integration Guide Revision 4
Introduction
SMK900 transceivers provide for highly-reliable, long-range, and low power mesh networking radio
applications. They use frequency hopping spread spectrum (FHSS) technology to ensure resistance to
multipath fading and robustness, as well as for compliance with 900 MHz unlicensed band regulations in
Canada and the US. The SMK900 supports a CTS-enabled serial port interface with data rates ranging from
1.2 to 230.4 kbps, with two possible modes of operation (transparent ASCII and protocol-formatted). For
easy integration, error correction and buffering is all accomplished within the mesh controller module. A
Virtual Machine is also available so that the user can leverage the module peripherals of the radio processor
to perform operation such as signal processing and remote control devices. The module accepts multiple
sleep synchronization clock sources: internal crystal, internal RC, or with an external I2C-line sleep
controller for optimal sleep management. Key features include:
● Multipath fading resistance, with more than 51 frequency channels, 902.7 to 927.4 MHz
● Receiver protected by low-loss SAW filter for excellent receiver sensitivity and interference
rejection
● Support for high-speed mesh networking applications
● Maximum range in free space exceeds 10 km (antenna height dependent)
● Typical range in forested areas between 250 and 500 m
● Transparent ASCII serial data mode for easiest integration available
● Advanced protocol-formated serial data mode available for maximum flexibility
● Accessibility to multiple analog and digital I/O via Virtual Machine
● Serial baud rates between 1.2 and 230.4 kbps
● AES 128 bits encryption available
● Module configuration stored in non-volatile memory
● Local and Over-the-air configuration for the radio
● Virtual Machine locally and remotely programmable at whim
● VM engine bytecode can be locally or remotely accessed/modified at whim via IDE
System
SMK900 System Overview
A SMK900 radio can be configured to operate in two main modes: gateway or node. A gateway controls a
whole mesh network and functions as the main coordinator node, and its usual primary function is to
bridge a host such as a PC, tablet, or internet gateway, with the rest of the mesh network. A node is a
transceiver that acts as a repeater inside of the mesh network. The primary function of a node is to
allow communication between an external devices and the gateway, or to serve as a bridge between
analog and/or digital inputs/outputs such as for sensor arrays.
It is possible to configure any node so that it filters messages by MAC address, or configure it so that it
acts like a sniffer relaying all messages transiting through the mesh network to the client circuitry via
serial port.
Mesh Network Systems
The topology used by a SMK900 radio is that of a broadcast-only mesh network, with sleep-wake
synchronization handled by the gateway. This mean that any SMK900 radio transmission sends a
broadcast to the whole mesh network. There are no provisions for pure unicast messaging, and such
needs are usually handled by integrator using a higher-level protocol sitting on top of the SMK900
protocol. The maximum of broadcast transmission of the same messages over the mesh network
depend on the number of hops allowed.
Multiple independent mesh networks may coexist in the same physical space by configuring nodes with
differing FHSS channels, different network IDs and/or different encryption patterns. Each of those
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