Raveon Radio Protocol – WMX

The Wireless Modem Exchange (WMX) – is an communication protocol available in all Raveon wireless modems. Data radio modems send and receive raw data, and in Raveon’s radios you can enable WMX messaging if you would like to use it.  WMX enables a user to have full control over sending and receiving of data:

1. Data Transfer:  Send and receive data to and from the local connected radio, or a remote wireless radio modems.
2. Remote Diagnostics: Send messages to remote devices to get status, voltage, temperature, and monitor system performance.
3. When sending: It allows the user to specify the destination ID.
4. When receiving: The source ID of data is included.
5. Internally, WMX messages are buffered, so mutliple WMX message can be setup to transmit as needed.
6. A WMX message can be tagged as a COMMAND message.
   1. The command can be immediately executed within the radio the WMX message come in to.
   2. The command can be targeted to a remote radio, and so it is sent over the air to a remote radio to execute the command.
   3. Command responses come back with identifications of the ID of the unit executing them, and the sequence number of the command.
7. Out-bound WMX messages has RSSI signal strength in them so the signal quality of the radio sending the data is very clear.

Without the WMX protocol, a Raveon wireless modem transparently sends and receive data to and from other Raveon modems, and the ID of the modems in the network are all pre-configured at time of installation. – You may download complete description of the WMX protocol here.

With WMX, the user my specify “on-the-fly” the destination ID of data that is to be transmitted. All received data is passed to the user in a pre-defined WMX format, so the source of the data may be determined. WMX also allows for sending commands to other radio modems. This enables the user to execute certain functions or control certain features of another remote modem – using the WMX Command protocol.

By default WMX is disabled on Raveon radios. To enable the WMX protocol, issue the WMX 1 command (WMX 0 disables it).

WMX is a serial port protocol. It is not over-the-air protocol because Raveon’s over-the-air protocol has all of the features described herein. WMX serial port protocol sends message to a radio telling it what to do (Execute a command, send data over air, send a command over are to some radio). When WMX is enabled and a radio receives data, it converts the data bytes into a WMX reception message with the data, plus ID code of the sender, the and the RSSI level.

WMX Highlights

• Provides an easy-to-use interface to a wireless point-to-multi-point network.
• Adds addressing capability to serial protocols and messages that do not have addressing.
• Simplifies user’s software development tasks.
• Allows the protocol to be implemented on 8-bit micro-controllers with limited resources.
• Provisions for addressing of transmissions by ID or group.
• Provides secure access to internal modem configuration settings.
• Provisions for unacknowledged data transmission
• Enables remote control of certain product features such as digital I/O and GPS tracking.
• Sequence numbers can be assigned to the message, or command, so receiving stations know which command sequence was sent or responded to.
• Makes Remote Diagnostics easy to do.

WMX Frames are used to pass data into and out of a radio modem. The bytes in the data field of the frame, field 6, contains the data that is transferred. The same frame format is used to send and receive data.

Detailes for the WMX protocol are in a PDF downloadable here:  WMXprotocol

The 16 Bit ID codes used in Data Radio Modems

To block the reception at one system from receiving data from a different nearby system, the modem IDs can be setup to have radios in the same System communicating only to the radios in their System.

All Raveon radios have 16 bit IDs in them, and the 16 bits can be used to communicate with  specific radios, or radio groups. WMX messages receive the ID codes, and also when an outbout WMX message is passed to a data radio, the 16 bit destination ID is specified, or if the destination ID is set to 0, the actual destination ID used will be the TOID set within the radio modem.
If a radio is ID 1234, this is the bit pattern of the ID:

In the examples that the table below uses, the first 8 bits of the 16 bit radio ID address to act as a user ascribed System ID, so there would be 255 unique systems that work separately. As long as the systems are 110+ miles away, they could have the same system ID and not receive each other.

If a system is setup so it does not interfere or communicate with another system nearby, a system can be assigned the first 8 bits.  Then every radio in the system will have the same first 8 bits.  And if each modem wants to have 8 different IDs assigned to it, the lower 3 bits will be allocated to each radio modem, so the middle 5 bits are actually the ID of the various radios in the system. When done this way, this architecture will allow 32 different radios in a single system, and 256 different systems that don’t step on each other.

The 5 Radio ID bits allow up to 32 different radios 00000 – 11111 in the Radio ID section.
The 8 System ID bits are used for 00000000-11111111 up to 256 different systems.

WMX is supported by all Raveon Radios shipped after January 2010