RFInsteon RF and Powerline Protocol: Message Formats
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This page covers Insteon RF and Powerline protocol fields and their functions, specifically focusing on the standard and extended message formats for both Insteon Powerline Protocol and Insteon RF protocol.
What is Insteon?
Insteon is a company based in Irvine, CA, USA. They developed the “Insteon” technology, which allows home devices to communicate using RF (Radio Frequency), Powerline communication, or both. This technology is used for smart lighting and electrical control applications, including home automation controllable via mobile devices, tablets, or computers.
Figure: A simple Insteon network consisting of Insteon RF devices, Powerline devices, Dual-band (PL+RF) devices, and an Insteon Hub.
The Hub is essential if you want to monitor and control your home devices remotely using a smartphone app. The Hub needs to be connected to the internet via a WiFi router or any other internet router (USB/RS232/Ethernet) available in your home.
Insteon technology defines two main types of packets for RF and Powerline communication:
- Standard packets
- Extended packets
Both packet types have standard and extended versions, and devices communicate using messages that are also classified as standard or extended. The structure of these messages is described below. Standard messages are 10 bytes long, while extended messages are 24 bytes long. Both types include fields for From Address, To Address, a Flag byte, two Command bytes, and a Message Integrity byte (CRC).
Standard Length Message
Insteon standard messages are 10 bytes in size. They are typically used for direct command and control operations. The payload consists of two command bytes. The specific fields are detailed in the table below:
| Fields | Size | Description |
|---|---|---|
| From Address | 3 bytes (24 bits) | Insteon sender device address |
| To Address | 3 bytes (24 bits) | Intended receiver device address; used for direct messages, broadcast messages, or group broadcast messages |
| Message Flags | 1 byte (8 bits) | 1 bit - Broadcast/NAK, 1 bit - Group, 1 bit - Acknowledge, 1 bit (zero for standard messages), 2 bits - counted down on each retransmission, 2 bits - Max. allowed number of retransmissions. |
| Command #1 | 1 byte (8 bits) | Command to be executed |
| Command #2 | 1 byte (8 bits) | Command to be executed |
| CRC | 1 byte (8 bits) | Cyclic Redundancy Check, used for error detection |
Extended Length Message
Extended messages include the same fields as standard messages. Additionally, they contain 14 bytes of arbitrary data used for uploads, downloads, encryption, and other specialized applications. The following table lists all protocol fields used in Insteon extended messages:
| Fields | Size | Description |
|---|---|---|
| From Address | 3 bytes (24 bits) | Sender device address |
| To Address | 3 bytes (24 bits) | Intended receiver device address; used for direct messages, broadcast messages, or group broadcast messages |
| Message Flags | 1 byte (8 bits) | 1 bit - Broadcast/NAK, 1 bit - Group, 1 bit - Acknowledge, 1 bit (‘One’ for extended messages), 2 bits - counted down on each retransmission, 2 bits - Max. allowed number of retransmissions. |
| Command #1 | 1 byte (8 bits) | Command to be executed |
| Command #2 | 1 byte (8 bits) | Command to be executed |
| User Data #1 to #14 | 14 bytes | User-defined data |
| CRC | 1 byte (8 bits) | Cyclic Redundancy Check, used for error detection |
Insteon RF Packets
When Insteon uses the RF band, messages are transmitted using RF frequencies, following the protocol structure described above. Insteon utilizes different RF bands, including 915 MHz (US), 869.85 MHz (Europe), and 921 MHz (Australia). RF messages are transmitted at a much higher speed compared to Powerline messages.
RF packets are smaller in size (14 bytes for standard and 28 bytes for extended messages), so they do not need to be broken up into smaller packets. Insteon RF packets contain 2 sync bytes and 1 start code byte at the beginning and a 1-byte CRC at the end of the packet.
Insteon Powerline Packets
When Insteon uses the Powerline band, messages are transmitted using a Powerline frequency of 131.65 kHz. Messages transmitted over the Powerline are divided into smaller packets. Each packet is transmitted in conjunction with the zero-crossing of the AC voltage on the Powerline.
As mentioned earlier, Insteon Powerline packets consist of standard and extended messages. Standard messages are five packets in size, while extended messages are eleven packets in size, with the following field definitions:
- SP (Start Packet) = {8 Sync bits, 4 Start Code bits, 12 Data bits}
- BP (Body Packet) = {2 Sync bits, 4 Start Code bits, 18 Data bits}
References
Insteon Developer’s Guide documents published by Insteon.com.
