Archive for the “Comunicaciones Radio” Category

The new version of MTXTunnel is now available, version v7.8. In this new version of MTXTunnel, I have included new features and enhancements suggested by MTXTunnel users. As always, the majority of suggestions do not fall on deaf ears. When interesting suggestions are not used they are written down and included in later versions, especially if they could be useful to other people. So if any MTXTunnel users have any suggestions, I welcome them with open arms!


These are the new features:

  1. It now has the ability to read 868MHz Wavelog radio devices (digital input radio equipment). Until now, it was only capable of monitoring Wavetherm radio devices (temperature), Wavesense (4-20mA and 0-5V) and Waveflow (pulse counters for metering applications).
  2. It now has the ability to send embedded AT commands via GPRS-RS232/RS485 gateways, whether it’s the server or client type. This means that it’s possible to send commands through a transparent gateway, like AT+CSQ for example. This command is used to remotely find out a device’s coverage. There are other commands for switching relays, changing settings etc. However this is very useful in scenarios with client type gateways who have telephone operators that do not allow server type connections (from a central PC to the modem) to run through Telnet.
  3. It has the parameter “DNS_mode: remoteat”. This parameter allows you to reproduce an MTX65i/MTX65IND modem’s digital input state in an MTX65IND’s relay. Therefore you can have a switch connected to a GPRS modem in Madrid and switch a modem’s relay in Miami. How does it work? Well basically when the modem detects a digital input change, it sends an AT command to a remote GPRS modem. On receiving this information, the GPRS modem switches the relays if necessary.
  4. It has the parameter MTX_flushSerialBuffers which allows you to clean the serial buffers before creating a TCP connection. Therefore it will delete everything that the modem’s serial port has read before establishing a 232/485GPRS- serial gateway.
  5. TCP_IP2 and TCP_port2 parameters have both been added. Before, you could configure the MTXTunnel to create up to two 232/485 GPRS-serial gateways that ran simultaneously (e.g. a single modem controlling two serial devices). But until now you could only create two “server” gateways. These two parameters now allow you to create two 232/485 “client” GPRS-serial gateways that work simultaneously.
  6. The MTX_clientReconnection parameter has been added. This parameter allows you specify the time (in seconds) that the MTXTunnel has to wait before reopening a client type 232/485 GPRS-serial gateway when it has been closed from the server. By default, it is currently 30 seconds. This means that the MTXTunnel opens a gateway against the server in order to exchange data. If the socket fails or is closed by the server, this parameter specifies the reconnection time.

Here’s the complete manual for the MTXTunnelv7.8. Remember that you can ask for it to be installed in GSM/GPRS modems:MTX65i, MTX65IND, MTX65INDv2, MTX65ULP, MTX65-RS485 y MTX65+G(and in 3G modems soon ;) )

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A looooong time ago I presented the MTX-INDv1 here which is a GSM/GPRS industrial modem with DIN rail format.  If we remember, that modem had a Cinterion TC65, therefore it was Java programmable with 400KB RAM and 1.7MB flash. It had 6 opto-isolated digital inputs (2 of which could also be configured as opto-isolated outputs), 2 analog inputs, 4 relays and an input power range of 8-30VDC. This modem also has a USB port and 2 ports which are configurable to RS232/485/422. As seen in the video, you could use an 868MHz Wavecard communications card to communicate with sensors via radio, such as Waveflow (pulse counters), Wavetherm (temperature sensors), WaveSense (sensors 4-20 or 0-5V …).

Nowadays we have the MTX-INDv2 version (the MTX-INDv1 version is still in production), which is the modem that I am going to present to those of you who have not heard of it. This is it in the following picture:

modem gsm gprs IP68

It’s basically the same modem ass a big part of the circuit has the same design as the MTX-INDv1. However it has improvements as it is designed for many scenarios that the MTX-INDv1 could not cover. The following are the MTX-INDv2’s characteristics and options:


-          It is based on the TC65i GSM/GPRS modem. Therefore it is Java programmable and it also has 400KB RAM and 1.7KB Flash. Alternatively, you can be provided with a TC65i-X internal module. It is exactly the same but with 2MB of RAM and 8MB of flash.

-          6 opto-isolated digital inputs ¡ (2 of which can also be configured as opto-isolated outputs)

-          2 analog inputs

-          4 relay 16A

-          USB port

-          2-port RS232/485/422


and here are the main differences:


-          IP68 waterproof box. This is ideal for devices that have to be used outside.

-          Power supply 220VAC or 24VDC. This means that you can connect it directly to a 220V network without needing a current adaptor, although it can also be used with 24V DC voltage.

-          It has a 1600mA internal battery which gives it various advantages. For example, you can use you Java application with 220V and if there is a drop in the voltage an alarm can be sent via SMS.

You have many other options:

-          You can order either a 25mW (1Km scope) or 500mW (4Km scope) Wavecard communication card.

-          You can order Ethernet-Serial converter which allows you to connect to a LAN network.

In short, it is an evolved version of the old MTX-INDv1 modem and it allows for a range of very important outdoor scenarios. Another day I will present the MTX-Remote (a series of 868MHz wireless sensors), and also the IP68. I am sure that they will be of interest for many applications that work seamlessly using the MTX-INDv2 as an 868MHz GPRS-radio communications hub.

For those who are interested, here is the MTX-INDv2 datasheet

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A month ago I posted about Coronis telemetry devices. We saw that they have IP68 devices that can read remotely via radio frequency (on the 868MHz band), digital inputs, 4-20mA or 0-10V analog inputs and temperatures/meters for water/gas/electricity. A lot longer ago, I also posted a video about the MTX-Industrial modem which you can optionally order with a Zigbee, Bluetooth or Coronis communications card.

So taking advantage of all of this, I have included an additional, interesting feature to the new MTXTunnelv5.6 (which is an application that as many of you know can be requested in any programmable MTX terminal). I have added a GPRS-Coronis communications gateway.

What do you use a GPRS-Coronis gateway for?

Let’s take an example. Imagine that you have a large area (several kilometres squared) with several hundred water meters that you want to read every day. A water meter quite simply generates a pulse (dry contact) for every X litres of water that flows through it. Therefore we will physically connect a Waveflow to each water meter. The purpose of each Waveflow is to count pulses that are generated by the water meter that it’s associated with i.e. said simply each Waveflow will know about the water that has flown through the meter at all times.

Obviously to read meters we could go to wherever they are every day with a PC + Waveport, but it would probably be better to take a reading from your own office as it’s warm in winter and cool in summer and you also avoid travel costs.  This is where you will find the new GPRS-Coronis gateway useful. Let’s look at this explanatory graph:


As you can see the communications hub is an MTX-Industrial (with optional internal Wavecard) + MTXTunnelv5.6.

Very good and how do I read the data from meters from my office?

Among all of its features, you can use Telnet with MTXTunnel. When connecting to MTXTunnel from your office via Telnet you can send AT commands (e.g. switch a relay remotely), read a digital or analog input, read GSM coverage etc. So I’ve added two simple AT commands called AT^MTXTUNNEL=SETWAVENIS,tramawavenis and AT^MTXTUNNEL=GETWAVENIS. With these two AT commands you can directly send Wavenis frames to the MTX-Industrial’s internal Wavecard via Telnet. This will allow you to read and connect to Waveflow meters.

Yes the MTXTunnelv5.6′s new feature doesn’t get rid of the fact that you have to take a look at the Wavenis protocol manual, but it can save a lot of work. For example if I want to communicate with a remote Waveflow I only have to do something like this:


This means that with “AT^MTXTUNNEL=SETWAVENIS”, we send the “frame in question” to a Waveflow and with “AT^MTXTUNNEL=GETWAVENIS” we get the response received from Waveflow. It’s as simple as that. The same goes for being used with any Coronis device, i.e. to monitor temperatures (wavetherm), distributed digital inputs/outputs etc. You have more information in the manual and of course if you have any doubts you can tell me on the blog or via email jose@blogelectronica /


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Perhaps we aren’t aware that we are being immersed in day-to-day life but without knowing it, the world is completely changing in leaps and bounds. Every day I see more and more different types of company projects that are trying to find a solution to radio frequency. We want everything to be automated, we want to measure everything, we want everything to be optimized, we want to control everything and we want to do all of this from a distance, without wires and without travel expenses.

Like all changes throughout history, any profound change has pros and cons. The upside of telemetry is obvious as we make considerable savings in personnel and we are able to control everything in real time. The downside is job loss. Any job where the main function is to go to a place to take a measurement or a something simple has its days numbered.

In today’s post I am going to describe some “finished” devices (i.e. boxed and ready to use). Some of them are well known to some of you, they are devices with the French brand Coronis (distributed in Spain by Matrix) e.g. Wavetherm, Waveflow, Wavelog, Wavesense, Waveport, Wavesense, and Wavetalk. As there are lots of devices I will give you a superficial description of them, just to give you an idea so that you don’t get tired of reading and writing. I will write about the devices one-by-one in more detail later.

All Coronis devices that I have just mentioned are radio devices that work in the 868MHz band (ISM band, this means a free band as you don’t have to pay for a license to use it). Apart from Waveport, all of the devices are “finished” in an IP68 box, this means that they are designed to work out in the open. They have an internal battery that allows them to be autonomous for up to ten years, I will discuss this later. These devices stand out for two things: the radio link distance and very low consumption.



Device for measuring temperatures. There are several options; you can purchase a Wavetherm that uses a Dallas DS1821 probe or the well-known PT100 and PT1000. It’s a programmable device, it can use logger and it’s possible to set a maximum and minimum temperature threshold which will then send an alarm message.


Telemetry device for energy, water and gas meters. It basically comprises of a pulse reader e.g. every time X litres of water circulates in a water meter, it opens/closes a dry contact. These pulses are “counted” by the Waveflow and it stores the measurements inside. Waveflows with 2 or 4 inputs are available.


Basically it’s a device for measuring digital inputs or controlling digital outputs. There are up to 4 digital inputs/outputs available.


Like Wavelog is for digital signals, Wavesense is in charge of analog signals. There are two versions. On one hand you have Wavesense for 0-10v signals and on the other hand Wavesense reads device’s outputs of 4-20mA.

Very good, I see that Coronis has lots of telemetry devices but how do I read them?

With Waveport.

Waveport is device that is available with two communication interfaces. With a USB port or with a RS232 port.  They are basically the same because whoever uses the USB version will actually have a Virtual COM (using a typical FDTI chip) therefore it works the same way.

Wave port is designed to connect itself to an intelligent device, to a communications hub (a PC or PLC etc.) i.e. something where there is a running program that’s responsible for saying to Waveport “go, tell me Wavetherm’s indicated temperature with the MAC address XXXXXXX”

What is the range of Coronis communication devices?

Well it depends on the type of device. Waveport and Wavetalk devices are available in 25mW and 500mW. The rest of the devices are only available in 25mW. In general terms 25mW Coronis devices can reach up to 1Km as the crow flies and the 500mW devices can reach up to 4Km.

And what happens if the distance is greater than mentioned above?

Well you can use Coronis relays, Wavetalk devices. When communicating with Coronis devices, you can insert up to 3 relays i.e. up to 3 Wavetalk devices. Therefore, when using 500mW devices you could have a radio link range of up to 16Km.

So is it always better to use 500mW devices than 25mW devices or not? 

Not really. They are more expensive, they consume more and unlike 25mW devices they don’t use FHSS (frecuency hopping) and therefore they are less immune to interference. You should use 500mW devices when you need to use them for greater distances.

Above you said that the battery lasts for up to ten years, is that true?

Yes, but it depends a lot on how you use the device and what you want it to do. It’s complicated so if you ever want to know how long your battery would last in a given scenario, tell me the details. To give you an idea, the battery from a Waveflow device that reads meters will last for around ten years if it takes one reading per day.

One reading a day? That’s not much…

Coronis devices (with batteries) are NOT designed for intensive use, at least not using the battery supply. They are devices that are designed to take a few readings over time so that they can spend most of the time in sleep mode. If for example you are looking for a device that does a meter’s telemetry ever 10 seconds, a Waveflow is not for you. You could use it, but it would flatten the battery within a few weeks.

Are the integrated batteries only in the IP68 version? I would like to integrate them like an OEM module in my own circuit so that I could use them with bigger batteries or even use a 220v adapter so that I wouldn’t have to depend on batteries. 

Coronis also have the OEM version of these devices. The limitation is the MOQ (Minimum Order Quantity). This means that if you have a project for 100 or more devices, you could purchase OEM modules. If it’s a small project for a couple of units you can’t get the OEM modules.

Well that’s enough for today. This is a very brief overview of these devices. We haven’t gone into any detail as these devices offer a lot more than what I have mentioned here. All we have today is a description; I will go into detail about Wavenis communication protocol, network architecture and communication hubs etc. in the next post.




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Today I had already started writing an article but then I changed my mind as I preferred to make a short video presentation on the new GPRS terminal that I’m sure will be interesting to more than one of you, in a while it’s going to be very well known.

It’s about the new Matrix terminal, the MTX-IND model, which is a terminal based on the powerful TC65i Cinterion module. I’m sure all of you know this GPRS module that allows you to embed Java applications and is based on an ARM9 like I told you a few months ago.

You’ll see it in the video that I made, but to whet you appetite I’ll tell you in advance that it’s a DIN rail GPRS modem, Java programmable, with 2 RS232/RS485/RS422 serial ports, relay outputs, opto-isolated digital inputs/outputs, ADC converters (0-2.4V / 4-20mA), USB and something even MORE interesting (which isn’t available yet) that you can only see in the video. ;)

Well then, here you have the video, I hope that you like it.

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As I said yesterday, today I’m going to present a new product that Matrix is going to distribute soon. It’s a firmware, only 7 Euros, for the MTX65 GPRS modem that we have already talked about (and of course we are going to keep talking about) in this blog. This firmware + the MTX65 GPRS modem are called MTX-Tunnel.

Basically MTX-Tunnel is a GPRS-serial gateway designed for remote maintenance application this means that you can avoid moving by simply connecting an RS232 serial cable to a device. It’s also designed to provide a GPRS connection to those devices that only have an RS232 serial port (e.g. meters, temperature sensors etc.).

There are other solutions, I’ve already told you about some on here like some Digi routers but the MTX-Tunnel has certain advantages in both performance and price that I will tell you about soon.


To be honest I have to say that this device is special to me, as I have quite involved with the firmware that goes inside the MTX65 and altogether they make the MTX-Tunnel.

That said, for those of you who are interested I’ll put more information on here like I usually do. You already know the question/answer routine.

What is the MTX-Tunnel device used for? 

The MTX-Tunnel is basically a GPRS-serial gateway that allows you to connect to an office with any device that has an RS232 serial port without moving via GPRS. You could do the same thing connecting an RS232 serial cable to the device; you can do it remotely via GPRS with MTX-Tunnel.

Is it complicated to set up?

In all, it is very simple. Basically you have to edit a file with notepad to configure certain parameters (IP, port, baud rate etc.). Once configured, simply drag the file inside the modem as if it were a pen drive. The MTX-Tunnel is then configured.

How does it work? Is it the MTX-Tunnel who connects to the central server in the office via GPRS or does it wait for incoming connections? In other words, does it act as a TCP/IP client or server?

It can be configured to work in two ways.

If MTX-Tunnel is configured to work in client mode, when you power it up it automatically connects to a server i.e. to a certain IP and port (specified in the configuration file). Once the connection is established with the server, all the data that comes from the server through the TCP/IP socket via GPRS is sent out through the serial port and vice versa. All of the data that enters through the serial port is sent towards the server through the socket via GPRS.

In server mode the MTX-Tunnel is connected to the GPRS and is stays listening through a certain port waiting to receive an external connection. Upon receiving the connection it behaves the same as in the previous case. When it comes via GPRS it is sent out through the RS232 serial port and vice versa.

Does MTX-Tunnel have to have a SIM card with a fixed IP address in client mode? 

No, not in this mode seeing as the MTX-Tunnel initiates the connection you don’t need to have a fixed IP. The server that is connects to has to have a fixed IP address, if it doesn’t you need to get an office router with DynDNS so that a DNS type yourOffice.yourDomain can tell you your company’s IP address.

And if it’s in server mode does it have to have a fixed IP address? 

It’s recommended but it’s not essential. If you have a SIM card with a fixed IP address it’s very quick to make a connection. If you don’t the IP you should work out the IP address assigned by the operator (Movistar, Vodafone etc.) to MTX-Tunnel when it connects to the GPRS.

And how do you find out the IP address that has been assigned to MTX-Tunnel by the operator? 

There are two ways. You can make a missed call or send an SMS to MTX-Tunnel. If MTX-Tunnel is configured to do this (indicated in the configuration file), the MTX-Tunnel will return an SMS to the phone number that sent the SMS or made the missed call, the SMS will contain the IP address that has been assigned by the operator.

So anyone who accidentally makes a missed call can get the device’s IP? 

No. In the MTX-Tunnel’s configuration file you can set up to ten valid phone numbers which can request actions like sending the IP address. If the telephone isn’t valid the MTX-Tunnel doesn’t do anything.

Does the MTX-Tunnel have to be permanently connected to GPRS? 

It depends. In client mode yes, the connection is permanent. As soon as the device has power it is connected to a specific IP address and port as I said before. If communication is lost for any reason, the MTX-Tunnel keeps trying to reconnect (every 30 seconds) until it is connected.

In server mode you do not need to be permanently connected to GPRS. If we want to be connected to GPRS at any point, all we need to do is make a missed call or send an SMS with the word “on”. Then you will be connected to GPRS and as I said in point 6, if configured to do so it will send an SMS with the IP address assigned by the operator.

And if MTX-Tunnel is in server mode and you don’t want the connection to be permanent, once you remotely activate the GPRS connection with the missed call or SMS, how do you disconnect from the GPRS connection? 

You can define a time out in the configuration file. Let’s suppose that you set it to 3 minutes. If the MTX-Tunnel doesn’t detect GPRS traffic after 3 minutes it will automatically disconnect from the GPRS network.

And if MTX-Tunnel works in server mode can you connect to any IP? I.e. can intruders connect to my devices? 

No. It’s the same with the telephone numbers. You can set up to 10 IPs that you can connect to in the configuration file. Any other attempted connection with an unauthorized IP is aborted.

But I already have a private VPN network i.e. I’m not going to have any unauthorized access to MTX-Tunnel. Do you need to specify authorized IP addresses like you said in the previous section? 

It’s not necessary. If you specify an authorized IP as you can connect to MTX-Tunnel from any IP address. Remember that this option is only recommended for VPN networks in order to avoid any unauthorized access.

Can you configure the MTX-Tunnel’s serial port parameters?

Of course. You can change the baud rate, flow control, data bits and stop bits. As always you can do all this through the configuration file.

Let’s imagine that we have 100 temperature sensors which are all the same, without any intelligence and all using 100 MTX-Tunnels in client mode i.e. all 100 are permanently GPRS connected to a server. If the MTX-Tunnels don’t have a fixed IP address, how do I know which temperature probe corresponds to which temperature that the server receives? 

MTX-Tunnel has a configurable identification parameter that allows you to set which is sent to the server first once the connection is established. With this you always know which device corresponds to which data in cases like I mentioned where devices work in client mode and don’t have a fixed IP address to send identification.

Will I have a problem with any up to date application that I use with a serial cable if I substitute it for an MTX-Tunnel? 

Usually not, but there is one thing that you should keep in mind. That is that GPRS communications are quick but they have a bit of a delay (just as it’s not the same to work with a LAN via the internet). Let me explain. If you have a question-answer application (a typical example of a PC questioning a temperature sensor), you have to take into account the time from when you send the command from via GPRS to when you receive the answer with the sensor’s data. This obviously will take more time than if you used a cable. It’s the only things that you have to keep in mind so that you can modify the timeout.

There’s more information on Matrix: / telephone 915602737

I hope that you found it interesting. See you next time, have a good weekend. ;)

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