Category Archives: GSM Blog

Should I buy a 3G intercom or alarm dialler?

We get asked a lot when the 2G network will be shutdown. In Europe, on the whole, nobody really knows yet.  The general consensus is that the 3G network will be shutdown first around 2020 and 2G as late as 2025.  In some countries 2G is no longer in operation (USA, Australia, Japan, Singapore…) but this is not the case in Europe.

Vodafone-will-not-switch-off-2G-until-2025

old phone

2G Phone

4G is obviously great for data but until recently many phone masts did not support audio on 4G/Long Term Evolution (LTE).  Audio on 4G uses a system developed by Qualcomm known as VoLTE.  Originally 4G was data only and your phone switches to 2G or 3G for calls.  Audio on 4G is really only being implemented now by most networks.

https://www.4g.co.uk/what-is-volte/

So, that leaves 2G and 3G for handling calls.  3G uses 2100MHz in Europe.  In general a higher frequency will result in a shorter range.  Also, on the higher frequency bands, your phone is limited by the amount of power it can transmit to 1W.  For comparison, on 900MHz 2G your phone can transmit 2W of power giving a better range.  The lower frequency of 2G and 4G bands will also penetrate walls better than the higher frequency 3G band.  3G also only has one frequency band allocated to it whereas 2G has two.

Europe-could-go-alone-in-waving-goodbye-to-3g-first

3G phone

Early 3G phone

3G therefore doesn’t really offer anything anymore.  It is slower than 4G for data and the coverage is usually worse than 2G which is why the network space is better allocated to 4G, 4G NB and 5G.

So, should you buy a 3G intercom or dialler?  We were developing 3G products but decided to stop simply due to their limited life-span.  They will work on 2G when 3G is shutdown but why pay the extra for a 3G unit?  There is one reason; in the UK the 3 network only offer 3G & 4G so you can only use a 3G unit on this network.  They may continue 3G beyond 2020 for this reason.  Also you may find you have no coverage in your area on 2G but there is coverage on 3G.  This would of course be a temporary solution for you!

3G Alarm Dialler PCB

3G Alarm Dialler

We gave up on 3G and I would not recommend paying extra for a 3G unit.  We are developing 4G products but these have many extra complications with VoLTE and network specific frequency bands so our 4G units are taking some time to develop – but 4G is the future!  We expect to be first with our 4G diallers and intercoms in Europe.

VoLTE Intercom

4G VoLTE Intercom

For further reading please see:

https://www.mobileworldlive.com/featured-content/top-three/operators-vendors-forecast-long-life-2g/

 

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Honeywell Accenta/Optima GSM Dialler SMS Sender – Set and Unset Alarm Remotely

Our C4 for Honeywell Accenta & Optima alarms allows you to remotely set and unset your alarm from anywhere in the world.  It will dial, text and email you when the alarm is triggered and armed and disarmed.

D4.01 GSM Dialer with SMS Voltage and Battery Monitoring Testing Video

Just a little video showing some testing being performed on the new D4.01 PCB.  This will be available on the website shortly.

The PCB has two analogue terminals for voltage measurement which can be sent by SMS or by email.  The supply voltage is also monitored for 12V battery operation.
It also has four high/low digital inputs and one volt-free relay output which can be operated by SMS or call.

Citadel Xr2 GSM Alarm Dialer/SMS Sender Wiring Guide Aico Smoke Alarm

We received this question via email:

Hi,

I would like to connect two devices to the Dialer:

Input One : Burglar Alarm

Input Two: Smoke Alarm

I have an Citadel Xr2 alarm system which I assume is pretty standard to get a signal from it [it is!].
The smoke detectors are from the Aico range, and would be interfaced through a Relay base Ei128RBU.

Cheers

Wiring the Citadel Alarm and Aico Smoke alarms to the Advent Controls GSM Alarm Auto-dialer and SMS Sender is very straight forward and the default input settings can be used.  The 0v terminal on the alarm panel and the GND terminal on the dialer must be connected together.  The bell -ve terminal is also connected to the selected input on the dialer.

Citadel Xr2 GSM dialer wiring with Aico Alarm

Citadel Xr2 Wiring Guide

The Aico Alarm has a set of relay output contacts which can be connected directly to Input B (in general ensure they are Volt-free and do not supply mains voltages!!).  Use the COM and NO terminals on the alarm as shown in the diagram.

For a basic setup you will need to send these messages:

master <your mobile number>.   (this sets your phone up as an administrator – remove red jumper afterwards)

callnum <1st number to be rung>.

callnum <2nd number to be rung>.  (you can keep doing this!)

textnum <text recipient>.

textnum <another SMS recipient>.  (again there is space for over 250 numbers)

If you would like the messages to say something specific you can send (for example):

customa the burglar alarm is sounding.

customb the fire alarm is sounding.

If you would like to know when the alarms have stopped sounding send these commands:

inlevela both

inlevelb both

customah the burglar alarm has stopped sounding.

custombh the fire alarm has stopped sounding.

The Advent Controls GSM Alarm dialer and SMS sender is available from the Advent Controls website here.

PAYG SIM Card Deactivation

When using Pay As You Go (PAYG) SIM cards in equipment such as dialers and gate openers you should be aware that the network may chose to deactivate your SIM card should you not meet the minimum usage requirements.  In the UK the strictest networks require at least a call or text message to be sent once per quarter – Lebara Mobile require 1 call/SMS per 3 28 day calendar months.

For details of the terms and conditions for each network I recommend following this link with an excellent article written on the subject:

http://kenstechtips.com/index.php/payg-inactivity-account-termination-and-credit-expiry

Further details can be found here on the basis for these policies:

https://community.giffgaff.com/t5/Blog/Recycling-mobile-numbers-giffgaff/ba-p/8211666

Our GSM equipment has two SIM card Keep Alive functions which automatically send an SMS or dial a number to keep your SIM card within the terms and conditions of the network.  All products have the Keep Alive Text feature which sends an automated SMS message at user specified intervals to their chosen number.  This is set up as follows:

KAT 07000000000,28.       Sends a keep alive message every 28 days to 07000000000

Dialers and Gate Openers with firmware version 3.18 or later additionally have the ability to dial numbers where a voice call is a requirement.  This is set up using the following command:

KAC 01512834306,80.      Dials 01512834306 every 80 days

Should the call go unanswered it unit will retry 4 times and will then send an SMS to the first master number with the following text ‘KAC@Fail’.  In this case a manual call should be made with the following command:

Dial 01512834306.     …or the number of your choice

Where your network requires a call to be made but your device has firmware prior to F3.18 we recommend setting the Keep Alive Text message to remind you to make a manual call for your required interval using the dial command.  Ensure the call is answered.

What’s new in July

We ended June having brought our new Gold G2 2-Button Intercom into full production and having restocked our old 1-Button internal aerial unit.

GSM Intercom

Advent Controls G2 Intercom

We have a new PCB which will form the basis of all of our dialers and gate/shutter openers going forward.  It features an ultra-low power mode, more inputs and outputs, space for a voice unit and Bluetooth.  The chip on the PCB has a larger program memory (like the hard drive of a PCB) giving us space to add more features.  The power supply design is more rugged too allowing for higher voltages and better surge protection.

B3 PCB

GSM Roller Shutter Controller

We’ve finally given up on the Circuit Switched Data (CSD) system we used for remotely connecting to devices in the field and have revised the software to use the GPRS packet data system.  We chose CSD as it meant your SIM did not require data and there was no need to tell the GSM unit your network’s APN (Access Point Name) e.g. giffgaff.com…  The problem is CSD does not really work at all never mind reliably.  Quectel have dropped support on the new modems we are using so it was time to switch to GPRS.

GSM assembly code

We’ll be using GPRS to dial in in future

There are huge benefits though.  The newer PCBs including our Gold G2 Intercom can have a full firmware update over the internet using GPRS.  We have also added the ability for the dialers and gate openers to send emails whenever activity is detected.  Eventually we will either offer our software to the end user or create a web interface for setup to be done online.

Setup GSM dialers and intercom online

Advent Controls Web Interface Software

New features – feedback definitely welcome!!

  • Dial, SMS and email
  • Bluetooth Setup
  • Low power modes
  • PC interface software
  • Ability to email list of settings and stored numbers
  • 2-In, 2-out PCB due August
  • Keep Alive text to display balance

Michael Beaver, Director