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Pro2 Master Module Communications

Pro2 Master Module Communications

The Pr02 Master Module is a flexible SCADA device for controlling valves and remote devices. It works great with with the long-range data radio modem that Raveon supplies to people who use this product. Raveon does not provide it, but it works with our wireless radio modems in remote areas. The Pro2 is designed to control lights, pumps, irrigation valves, beepers, door locks, and many other electrically controlled devices. The 8 output signals switch DC voltage and are reliably protected against Electro-Static Discharge (ESD) and lightning surges.

The controller interface uses Ethernet or RS232 interfaces, so the Pro2 is often used with Raveon’s long-range data radio modems. The advantages of using wireless data radio modems to communicate to the Pro2 are:

  1. Long Range communications. Using Raveon’s wireless modems, you can control Pro2 so over 100s of square miles.
  2. Multiple connections. Raveon radios have 16 bit IDs, so 65000 Pro2 can be communicated to in unique and secure ways.
  3. Secure communications. Raveon’s wireless modems utilize secure AES encryption, so it is secure and reliable to communicate with. If only wires were used, the system would easily be able to be hacked.
  4. Low Cost. Installing and running wires across hundreds of meters is expensive, where wireless connections need very little labor to install. And wireless connections can be moved around every easily unlike wired connections.

What are the features of a Pro2?

  • ON – OFF control of valves, lights, and other devices. No need to run back to a PC to turn a zone on (or off).
  • Each output has a LED to indicate if it is running or idle.
  • All valve wires and connections are protected against lighting surges.
  • RS232 and network connections protected against ESD and lighting.
  • The 8 outputs are protected against overloading by a self-resetting electronic fuse.

Using Data Radio Modems to communicate with SCADA devices like this Pro2 or a Rain8net:

Raveon’s RV-M21 series of data radio modems have RS232 serial interfaces that work with the PC controller and all of the remote controllers in the field.

Fast Long Range Radio

This is information about a communication time test with an oscilloscope to measure and show how fast our long-range LoRa technology works.

Below is a picture of the data communication time.

The Green pulses were inbound 16 bytes of data on a UART into Radio #1 at 38400bps.

The Yellow pulses are the outbound 16 bytes of data on a UART in Radio #2 that received the over-the-air message from #1.

So from the time the first message was sent into the radio it fully came out of the other radio in 40mS. 

This is Raveon’s RV-M50 ISM band transceiver that uses LoRa technology.

This message passed along over the M50 radio modes was doen with them in the spreading factor of 7. With LoRa technology, there are many spreading factor options to utilize. Following is a list of over-the-air data rates for LoRa data radio modems.

In Raveon Radios, Channel data rate varies by spreading factor, spreading factor can be set with ATSF <val>, where <val> is set according to the table below:  

ATSF Setting Bit Rate for 500kHz Channels Duration for 20 Data Bytes Dur. 100 Bytes
Typical Packet FEC=0(4/4) FEC=1(4/5) FEC=4(4/8) FEC=1(4/5)
7 21.87 kbps 20mS 25mS 30mS 52mS
8 12.50 kbps 44mS 44mS 56mS 92mS
9 7.03 kbps 64mS 78mS 100mS 160mS
10 3.90 kbps 125mS 144mS 184mS 310mS
11 2.14 kbps 240mS 265mS 340mS 580mS
12 1.17 kbps 480mS 520mS 680mS
(Don’t Use)
1020mS (do not use)

For packets greater than 10-20 bytes, we recommend not to use Forward Error Correction FEC 4(4/8) with the Spreading Factor ATSF of 12, because packets are too long for the system. 

The fast efficient over-the-air protocol is ideal for sending data between RTUs and between Master Controllers and RTUs. This RV-M50 radio modem can send information between two devices 20-50 times per second, and even get responses back in 40mS, so a round-trip inquiry can take place in 80mS out and back.

Using RF Modem ID Codes

Raveon has products with various radio identification ID features.  Each radio has an ID, and is assigned and ID to talk to.  This Application Note AN240 describes how ID processing works and describes all the ID features Raveon’s radios have that use the IDs such as broadcasting and repeating. 

Addressing Basics

One of the more powerful aspects of Raveon’s Radio Modems are its addressing scheme.  Addressing allows multiple radio systems on the same frequency to co-exist, and not interfere with each other.   Addressing is used to differentiate one radio modem from another.  Each unit has a unique number, so that when data or a GPS position report is received, the radio modem  that sent the message is known.  Use the Data Encryption Security KEY to protect messages from being intercepted.  Use the ID addressing to identify individual radio modems and GPS transponders.

This addressing scheme allows up to 65,000 (FFFF) radio modems to be on one radio channel, or split-up into sub-groups. A way to disable addressing altogether is set the Address Mask to 0000 (ATMK 0000 command).
For More Technical information about how to utilize Radio ID codes, read Application Note AN240.

You can also setup radios in Groups by using the Address Mask as F000, FF00, or FFF0 depending upon the group size you would like. F000 masks of the three lower ID numbers, so only the first number in the ID needs to match.

One effect of this is that an address mask of 0000 will cause the Radio Modem modem to received any data from any unit that transmits.  The Destination Address will effectively be ignored and all data received if the mask is set to 0000.

Listen Address:

The Listen Address is a second ID programmed into the radio, that the unit will Listen for.  The Listen Address is configured using the ATLA xxxx command.  If the Listen Address is set to FFFF, then this feature is ignored, and FFFF is the factory default so by default the Data Radio Modem does not use the Listen Address.

Store-and-Forward Repeating

The RADIO MODEM modem has a built-in wireless repeater.  Each RADIO MODEM is capable of not only sending and receiving data from/to its serial port, but also re-transmitting data packets it receives over-the-air data. 

Automatic Repeater Configuration

The easiest way to enable store-and-forward repeating is the use the REPEAT 1 command. REPEAT 1 will turn on the store-and-forward feature, and configure it to repeat all packets the radio can hear on the air.  REPEAT 0 disables store-and-forward repeating.

It is highly recommended that you use this method to configure your RADIO MODEM as a repeater.

Important:  The Unit ID of the repeater must be unique in the system. No other radio modem in the system can have the ID of the repeater.

Serial Data Communications

Electronic communications is all about interlinking circuits (processors or other integrated circuits) to create a symbiotic system. For those individual circuits to swap information, they must share a common standard communication protocol. Many communication protocols have been designed to achieve data exchange.

The most common serial communication protocols are RS232, RS485, RS422, USB, and Ethernet.  But because USB and Ethernet require powerful interfaces with complex protocols, many efficient devices utilized RS232, RS485, and RS422 which is what this note is all about.

Serial Communications RS232, RS485, RS422

AN236 Summary

AN236(SerialComm) Application Note PDF

Electronic communications is all about interlinking circuits (processors or other integrated circuits) to create a symbiotic system. For those individual circuits to swap information, they must share a common standard communication protocol. Many communication protocols have been designed to achieve data exchange.

The most common serial communication protocols are RS232, RS485, RS422, USB, and Ethernet.  But because USB and Ethernet require powerful interfaces with complex protocols, many efficient devices utilized RS232, RS485, and RS422 which is what this note is all about.

Protocol Comparison Chart

RS-232 RS-422 RS-485
Cable Single ended Single ended multi-drop Multi-drop
Number of Devices 1 transmitter
1 receiver
1 transmitter
10 receivers
32 transmitters
32 receivers
Communication Mode Full duplex Full duplex,
Half duplex
Full duplex,
Half duplex
Maximum Distance 50 feet at 19.2 kbps 4000 feet at 100 kbps 4000 feet at 100 kbps
Max Data Rate (50 feet) 1 mbps 10 mbps 10 mbps

Serial Protocols

The RS232, RS485, RS422 serial protocols only relate to the hardware interface, not the software protocols used to make the devices communicate. There are many protocols that exist in the market place so one cannot assume interoperability between different manufacturers of “RS232” ports.

To define Instruments that supports a mixture of industry standard and proprietary serial protocols:

Modbus RTU

This protocol is used in industrial applications and most SCADA PLC’s have drivers for Modbus RTU. The Modbus protocol is well published and every manufacturer can and does determine its own addressing scheme. The manufacturer must supply the addressing scheme, register type, and Modbus commands that is supports.

ASCII protocol

ASCII is popular because it is easier than Modbus to write your own driver in a PLC or a PC. Most every manufacturer’s protocols are not usually compatible.

The Advantages of RS485 and RS422 vs RS232

RS485 and RS422 use differentiation. Two wires are required for each signal.  The figure below shows a single RS485 / RS422 signal being transmitted. To transmit a logic 1, line B is high and line A is low. To transmit a logic 0, line B is low and line A is high. The advantage of this arrangement is that signals can be transmitted faster and over greater distances than is possible with a single wire.

The main difference between RS422 and RS485 is the types of communications allowed. RS422 allows only one-way (simplex) communications between one driver, and as many as ten receiving devices. To control devices and need no feedback from them, RS-422 multidrop network will work well. RS485 was designed to address the multi-drop limitation of RS422, allowing up to 32 devices to communicate.


An RS232 serial bus consists of just two communication wires – one for sending data and another for receiving. As such, serial devices should have two serial pins: the receiver, RX, and the transmitter, TX.  Because the communication data is based upon the voltage on the wires, relative to the ground level, a ground connection must be made between devices that communicate with RS-232.  Here is an RS232 wiring diagram:

A digital 1 voltage is:  -3V to -25V

A digital 0 voltage is:  +3V to +25V

RS232 data is sent serially, each bit is sent one after the next because there is only one data line in each direction. This mode of data transmission also requires that the receiver knows when the actual data bits are arriving so that it can synchronize itself to the incoming data. To achieve this a logic 0 is sent as a synchronization start bit.


RS422 is designed to be tolerant of noise and forgiving of long cable runs. It achieves this by using a differential current drive output which has high immunity to noise. The noise immunity enables RS485 systems to operate over very long connections, much better than RS232, US, and Ethernet.

Each signal uses two wires to pass the data. The differential voltage on the A and B wires represent the digital value. If B>A the value is 1. If A>B then value is 0.

Input Signal   A    B Output Signal
0   1     0 0
1   0     1 1

RS422A Standard Specifications

  • 1 Driver, up to 10 Receivers

Line Length for Max Data Rate:

  • 40 Feet = 12m 10 Mbits/sec
  • 400 Feet = 122m 1 Mbits/sec
  • 4000 Feet = 1219m 100 kbits/sec

A multi-drop wiring has many desirable advantages, RS422 devices cannot be used to construct a truly multi-point network. A true multi-point network consists of multiple drivers and receivers connected on a single bus, where any node can transmit or receive data.  RS422 networks are often used in a half-duplex mode,


RS485 is still popular. It is similar to the RS422 upon which it is based. The RS485 port has been used for many years.  RS485 has many advantages over both RS232 and USB when it comes to applications in noisy industrial environments. RS422 devices can be used on an RS485 bus network if they are only used as recipients.

The main difference between RS422 and RS485 is that up to 32 transmitter receiver pairs may be present on the line at one time on RS485. A 120 Ohm resistor must be used to terminate the main line.

RS485A Standard

  • Up to 32 Driver/Receiver Pairs

Line Length Max Data Rate

  • 40 Feet = 12m 10 Mbits/sec
  • 400 Feet = 122m 1 Mbits/sec
  • 4000 Feet = 1219m 100 kbits/sec

When instruments are described as having an RS485 interface this tells you nothing for sure about the signals being transmitted. Usually though only the Transmit Data (TX) and Receive Data (RX) of a normal serial port are converted to RS485 or RS422. The other signals of the serial port are not used. Three arrangements are commonplace: Write only, 4-wire (full duplex) and 2-wire (half duplex).  The  “2-wire” RS-485 connection is shown below.

RS485 half-duplex can use just two wires to communicate with up to 32 device, one at a time.  Each device has the ability to turn off its output drivers, so only the one device that is linking to the host outputs a signal on its TX lines.

Termination Resistors

Termination resistors should be placed on both ends of the twisted pair of wires. The impedance value should be the same value of the characteristic impedance of the twisted pair and should be placed at the far ends of the cable.

For cables that are 2000 feet or less, a termination resistor is not needed at baud rates of 9600bps or less.

If a termination resister is required, a 120? or greater should be used.  No more than 2 termination resistors should be used, one at each end of the RS485 transmission line.

For additional information, contact:

Raveon Technologies Corporation

2320 Cousteau Court

Vista, CA 92081 – USA

Phone: 1-760-444-5995
Fax: 1-760-444-5997

WayWORD Mobile Data Terminal Accessories and Kit

Cable Part Numbers

4C001-30   Power Cable 

    • Cable, 3-pin, female connector, locking, 3 meter length
    • All WayWORDs will come with a power cable, regardless of setup used.

4C806-MF-10  DB9 Data Cable 

    • Data cable black with DB9 female, 10ft.
    • All WayWORDs will come with a DB9 Data Cable.

 4C010-30 External I/O Cable

    • Cable, Assembled, 22 AWG, 12 Conductor, 3m
    • Optional

4C806-Y-10  Y Cable

    • Cable, DB9, Black, M/F, Y-branch, 2 Outputs
    • Systems that require only a small number of external IO pins may utilize the Y-cable to make use of pins normally dedicated for handshaking to be used for their own IO.
    • Optional

Standard MDT Kit

  1. RV-DT-8R
    • MDT, 4×24 LCD, with RFID reader, 10-30V DC
  2. 4C001-30
    • Power Cable, 3-pin, female connector, locking, 3 meter length
  3. 4C806-MF-10
    • DB9 Data cable black with DB9 female, 10ft.
  4. Gift Box
    • 8 15/16 x 8 7/16 x 2 9/16

Other Accessories

  • RV-DT-K2
    • RFID Key FOB
  • RK-PD-1
    • Mount, MDT, 2″x2.5″ Plastic Plate with a 1.0″ Diameter Ball
  • RK-PD-2
    • Mount, Rail Base w/ a 1″ Ball to Attach to Pipe or Handlebar
  • RK-PA-1
    • Mount Arm, 2.28″ Adapter Arm to Connect 2 RAM 1″ Ball Mounts
  • RK-PA-2
    • Adapter Arm, Connects two RAM 1″ Ball Mounts, 6″ length


Verifying Radio Communications and Path Signal Strength – PING a Radio

Whenever 2 or more data radios are installed to communicate wirelessly, a vital design point is to establish that the radios are in communication with one another.  Another design point to verify is that the effective radio signal path is sufficiently robust to provide reliable and consistent communications.  Both of these objectives can be realized by becoming familiar with and utilizing the PING feature in any Raveon data radio modem.

The PING of a remote radio is very similar to the PING of a remote IP address.  In each case, the PING command is issued from a local device, the address of the remote device is specified, and if successful, the remote device automatically responds to the PING with the local device displaying the results.  For a PING to be successful, communications in both directions between the local and remote device must take place.  If a PING fails, one or both directions of communications may be assumed to have failed.

To PING a remote Raveon radio modem, several conditions must be met.  First, both devices must be set to operate on the same frequency (ATFR, ATFT, ATFX parameters) the same bandwidth (ATBW parameter) and the same over-the-air baud rate (ATR2 parameter).   Next, both radio modems must be operating in packet mode (ATMT parameter set to 0) and have unique valid addresses (MYID or ATMY, TOID or ATDT, and ATMK parameters).  Additionally, as PING is a Remote Procedure Request (RPR) that includes a message return from the remote radio ensure that TDMA channel access is disabled and the radios are operating in CSMA (Carrier Sense Multiple Access) mode. If you have a GPS enabled radio setting GPS mode 0 will accomplish this.  Finally, both radio modems should have remote access enabled (ATRV parameter set to 0).

To PING a radio modem, enter into command mode on the local modem and issue the following command:


Where XXXX is the 4 digit address of the remote device (e.g. PING 1002).

Alternatively, you may utilize Raveon’s free-to-download Windows GUI radio configuration utility Radio Manager.  The PING execution is found on the interaction tab.

When the remote radio modem responds to a PING, and the response is received, the local radio modem will display a brief result without indication of error and include the RSSI (Relative Signal Strength Indicator) signal level of the responding (reply) transmission.  To capture the RSSI of the outgoing (request) transmission, you must initiate the PING from the opposing radio, and capture the RSSI from this response.

Here is an example of a successful  PING.  In this case the PING is from modem 1001 querying the remote modem 1002:

Ping 1002




In the successful PING please note that an RSSI value of -90 is returned.  This RSSI information can prove quite valuable. -90 means the receive signal strength was -90dBm.

Whenever installation trouble is encountered, and two radios do not appear to be communicating, it is a good idea to try and execute a PING.  If the PING succeeds, you have verified that the two radios are in fact communicating, and you may consider other aspects of the system as potential failure points.  A PING can also be a valuable tool in aligning directional antennas, which should accurately point towards the opposing target.  While RSSI numbers are relative, generally an RSSI with a value closer to zero than -100dB (i.e. -97, -85db) will be strong enough to support good radio communications.   Note that this is not strictly the case, especially in environments where there is a lot of noise on the frequency in question.  You should always look for a 20dB difference or more between your signal strength and background noise.  For instance, if you background noise level is on average in the vicinity of -115db, you want an RSSI value of at least -95db, with -90, or -85dB being preferred, and providing some buffer against occasional noise spikes.

To acquire an instantaneous reading of the background noise level, ensure no device in the system is transmitting, and then type the command ATRQ.  The background noise level will be displayed.

To strengthen the signal of a transmission you can consider several actions. First, if the output power on the radio modem is not already set at 100% (ATPO parameter), you can increase the output up to 100%.  Second, consider slightly repositioning our antennas, use higher gain antennas, or lower loss or shorter antenna cable.  Third, install a power amplifier.   Raveon can recommend and source several amplifiers.  In any case, ensure none of these remedial actions violate your radio license limits.


Author: Larry Topp

The LoRa Protocol


LoRa is short for “Long Range”.  LoRa modulation scheme is a modulation technique combined with a data encoding technique that gives a broad-band spread-spectrum radio the receive sensitivity of a very narrow-band long range radio. Many people are not looking into what is LoRa, and this document describes LoRa and the advantages the LoRa technology has brought to the communication world.

LoRa techniques give LoRa receivers unprecedented sensitivity levels. LoRa radio modems can receive signals 10 times weaker than most radios.

When a receiver’s sensitivity is increased by 10 times, that is the same communication range improvement as increasing the transmitter power 10 times. But with LoRa you get the great range improvements without any increase in power consumption or transmitter power. And most license-free bands restrict transmit power, so LoRa is the best way to increase the communication range of a wireless data link.

Raveon is one of the many early implementers of the LoRa technology in the USA, and one of the first to get a full-power LoRa device FCC certified. LoRa is a radio modulation technique and protocol that enables a device to have an unprecedented long-range. See our LoRa products at

Forward Error Correction

FEC is commonly used to increase a receiver’s sensitivity by reducing the bit-error rate of the system. LoRa radios have integrated FEC into the protocol. FEC effectively increases the energy per bit and enables the device to correct for bit errors. By adding extra overhead bits to groups of bits being transmitted, the data throughput gets reduces but the bit-error-rate is lower with weak signals, increasing the sensitivity of the receiver.

Interference Immunity

There are a number of different types of interference all wireless systems must deal with:

  1. Co-channel interference. This is where there is some other transmitter on the exact same frequency that the system is currently utilizing. Many RF systems stop working if the interference is even 10dB weaker than the signal being received. With LoRa, the interference can be as much as 19dB larger than the signal being received and the receiver will still get the signal. This means LoRa systems will keep working reliably as the frequency channels get crowded.
  2. Blocking Rejection. Sometimes a system needs to operate in a location where there is a powerful interfering signal nearby. For example, in the USA the 906-924MHz ISM band that LoRa uses is only 50mHz away from the 800MHz radio bands where powerful narrow-band transmitters emit 100watts, or 2watt cellular 869-894MHz transmitters. Even though LoRa is 10 time more sensitive, it is even 20 X less susceptible to overload from these powerful out of band signals.

Link Margin Comparison

When one compares a LoRa radio system to a traditional UHF or VHF radio modem, we see that the communication range for LoRa is very similar to VHF and UHF, but it achieves this with much less RF power.  The spreadsheet calculations below show the theoretical link margin for LoRa 900MHz compared to VHF and UHF radio systems.

LoRa 200mW LoRa 10mW UHF 2W VHF2W
Operating Frequency (MHz) 915 915 460 160
Transmitter Output Power 23 dBm 10 dBm 33 dBm 33 dBm
Link Distance, km 180 km 40 km 150 km 450 km
Link Distance, miles 111 mi 24 mi 93 mi 279 mi
Transmit Antenna Gain (dBi) 5 5 3 3
Antenna feed loss (both ends) 1 dB 1 dB 1 dB 1 dB
Receive Antenna Gain (dBi) 5 5 3 3
Receiver Sensitivity -128dBm -128dBm -115dBm -115dBm
System Gain  (dB) 151 138 148 148
Link Fade Margin  (dB) 22.2 22.3 22.8 22.4
Link Path Loss  (dB) -136.8 -123.7 -129.2 -129.6
Effective Radiated Power 27 14 35 35


The theoretical calculations show that a 200mW LoRa radio will work about as long-range as a 2watt UHF radio.  A 2watt VHF will work a bit longer range but it is using 2 watts. Raveon’s field tests support these theoretical calculations.  We’ve seen VHF and UHF reliably go 50-100 miles line of site, and LoRa can easily go 20-50 miles (at 1/10th the power consumption).

Although, building, forest, and foliage penetration is much better with VHF and UHF radio technology, so 900MHz systems will typically require taller antennas at the base stations and more base stations to get good coverage. This is offset by the cost and power of LoRa radios being so much lower than traditional VHF and UHF systems so building out large area networks with LoRa is a very good approach.

LoRa Modulation

The over-the-air modulation method that LoRa uses is a type of Direct Sequence Spread Spectrum (DSSS) they call Chirp Spread Spectrum (CSS). Each bit is spread by a chipping factor. The number of chips per bit is called the spread factor. Lora also sweeps the modulation across the channel, so that the occupied bandwidth of the transmitted signal matches the choose bandwidth.

The larger the spreading factor, the slower the over-the-air data rate. And as mentioned before, the slower the data rate, the better the receiver sensitivity and the longer the potential communication range. For an example, here is how a spreading factor of 7 affects the bits sent over the air.



Typically, a LoRa radio uses 125kHz, 250kHz, or 500kHz radio channels.Below is a table showing the over-the-air data rates at the various commons spreading factors LoRa uses on these three channel bandwidths.

LoRa Over the Air (OtA) Baud Rates

The OtA data rates listed below are in kilobits per second. This table assumes the LoRa coding chip rate is set to 1.

Spreading Factor 125kHz B.W. 250 kHz B.W. 500 kHz B.W.
5 15.625 31.25 62.5
6 9.375 18.75 37.5
7 5.46875 10.9375 21.875
8 3.125 6.25 12.5
9 1.757813 3.515625 7.03125
10 0.976563 1.953125 3.90625
11 0.537109 1.074219 2.148438
12 0.292969 0.585938 1.171875

LoRa RF Power Output

In the USA, LoRa systems typically use a combination frequency hopping and direct sequence modes, to keep in compliance with FCC requirements. A hybrid system can use some 125kHz channels and one direct sequence as long as the power limits and dwell limits of the regulations are met.


To keep the transmit power level in compliance with the PSD limits, a 125kHz channel has 41 3kHz windows, so the max power is 41 X 6.3mW = 258mW (24dBm).  If 500kHz channels are used, then the transmit power can be 4X that (1watt) on the 500kHz channel.  To account for modulation peaks and some bandwidth margins, typical LoRa power levels are about ½ the theoretical limit which will ensure regulatory compliance.


Raveon’s LoRa base stations utilize LoRa chips that have the ability to receive 8 channels all at the same time. No other long-range wireless technology has this multi-channel receiver capability.

By having the ability to receive 8 channels, 8 wireless nodes can report in at the same time, and as long as they are on different RF channels, the base station can receive them.

LoRaWAN Frequencies

The LoRaWAN protocol specifies that certain frequencies in certain countries shall be supported by every device.  These are listed as:

  • EU 868.1, 868.3, and 868.5 MHz
  • EU 433.175, 433.375 and 433.575 MHz
  • China 779.5, 779.7 and 779.9 MHz.
  • North America  US 902-928MHz.

Be sure to visit the Raveon Blog for more information.

Digital Mobile Radios (DMR)

What is DMR?

Digital Mobile Radio (DMR) technology was developed by the European Telecommunications Standards Institute (ETSI). DMR is used worldwide
by professional mobile radio users. DMR digital mobile radio use a 2 channel TDMA, time division multiple access scheme. TDMA radios use a time slot to communicate together, which helps avoid interference.

The great benefit of DMR is how it provides multiple voice channels for every one RF channel. It does this by using two-slot TDMA (Time Division Multiple Access) technology. A 12.5 kHz channel is divided into two independent time slots. DMR achieves the 6.25 kHz channel equivalence (6.25e), specified by many global regulators seeking greater spectral efficiency. DMR is designed to work for consumer and short-range business users. They require low power, and are cost-optimised radios. Even professional users for whom radios are critical to their business or organization, and emergency services for whom radios are a vital mission critical tool, DMR is reliable and efficient. Have a private radio network can cover the required area as needed. With DMR base stations connected to wide area networks, a DMR system can cover a city, state, country, or globe.

DMR has three tiers.

Tier 1 (Unlicensed) is a single channel specification originally for the European unlicensed dPMR446 service. It is a single channel FDMA 6.25 kHz bandwidth; the standard supports peer-to-peer (mode 1), repeater (mode 2) and linked repeater (mode 3) configurations. Tier I standard has been expanded into radios for use in other than the unlicensed dPMR446 service.

Tier 2 (Conventional) is 2-slot TDMA 12.5 kHz IF peer-to-peer and repeater mode
specification. Each time slot can be either voice and/or data depending upon system needs. Most amateur radio implementations of DMR are using voice on both time slots. Any brand DMR (Tier 2) radio will work on a Tier II system.

Tier 3 (Trunking)was built upon Tier 2, adding trunking operation involving multiple
repeaters at a single site. Vender specific protocols expanded the
trunking to multiple site operations.

The current implementation of DMR utilizes the DSVI AMBE+2™
vocoder; it is not specified in the ESTI standard. Most of the radio manufacturers have implemented the vocoder in licensed software.

  Talk Groups (TG)

Talk Groups (TG) are for groups of users to share time slots without distracting and disrupting other users of the time slot. Note that only one Talk Group can be using a time slot at a time. If a radio is not programmed to listen to a Talk Group, you will not hear that Talk Group’s communication.

Base Stations

The DMR Base Station has a CACH data channel transmitted between the individual TDMA bursts. This enables the base station to transmit announcement information to DMR mobile and portable devices.

DMR systems support both voice and data services. On a trunked network, channels can be dynamically allocated as required. With DMR, priority levels ensure traffic with the highest priority will get passed through.

The maximum coverage of a TDMA system is indeed influenced by distance. Most DMR vendors, provide 0.5ppm frequency accuracy in the terminals. The theoretical limit is around 150km. There are many other factors that impact radio coverage. There are many DMR systems deployed with coverage areas of up to 100km. 

DMR radios satisify the FCC’s narrow-band mandate by being 6.25 kHz equivalent. DMR is more spectrum efficient than other 6.25 kHz modes since no guard band is needed for the two channels. DMR as 1/3 the channel RF bandwidth of an analog 25 kHz radio signal. It also has extended battery life and great voice quality, often better than other digital voice radios.

Remote Weather Monitoring

Remote weather monitoring Raveon’s data radio products are well-suited for remote weather monitoring. Raveon VHF and UHF radios are long-range (5-50 miles) and very rugged. Operating from -30C to +60C, they have 5 watts of RF output and consume very little power.

Raveon’s Wireless Telemetry Product Features

  • RS232, RS422, and RS485 serial interfaces
  • Easy to use with built-in smart radio modem. Data In = Data Out.
  • Works with MODBUS, DNP, and most serial SCADA protocols.
  • 1/2-5 watts of RF output in the 450-480MHz (other bands available)
  • Range of 5-50 miles
  • Ultra-fast T-R switching time of 3mS
  • Store-and-forward repeater capability
  • Exceeding all FCC part 22 and 90 requirements

Products for the Oil and Gas Industry

M7 Wireless Modem

M7s Series UHF Wireless Modems

Ideal for SCADA and Telemetry applications, the M7 series of products features: 1/2-5 watts of RF output in the 450-480MHz (other bands available), range of 5-50 miles, ultra-fast T-R switching time of 3mS, store-and-forward repeater capability, remote “Ping” capability, voltage, temperature, and current monitoring, and RS232/422/485 interfaces available.  Perfect for SCADA, remote control, telemetry, mobile-data, and AVL applications.

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M5 Wireless Modem Raveon’s RV-M5 FireLine series of VHF data radio modems are a high-speed FCC refarming compliant data radio designed for telemetry, wireless data, GPS, and remote control applications.  They operate in the 136-174MHz frequency band, with up to 5 watts of RF output.

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