In the article we look at which GSM masts are available to us at our location and see which network will give us the best performance. We also look into establishing a data connection using the CLX SIM card and find the location of our PCB using QUECELL locate system.
We had a board hooked up with 2-way comms to a PC whilst developing the speech storage and playback function on our GSM Alarm Speech Dialler ADs (available at http://www.adventcontrols.co.uk). We took this opportunity to investigate the network infrastructure we are able to acquire here in our office
Firstly, we send the command AT+CREG? which shows us that the modem is connected and roaming. We are roaming as we are using the CLX SIM which has access to any GSM network in the UK.
Next, we send the AT+QOPS? command to get a list of masts the M66 is able to acquire:
+QOPS: 1,”Vodafone”,”Voda UK”,”23415″
+QOPS: 2,”O2″,”O2 -UK”,”23410″
1,53AC,9BDA,27,23,111 (n.b. 9BDA in hex is 39898 in decimal)
QOPS: 2 shows us we are currently using the O2-UK mast with location code 53AC and CellID 9BDA. We can also see masts from T-Mobile (part of EE) and Vodafone are available to us (QOPS:1). With the CellID we can find the mast we are using on a map
Earlier we were using an EE SIM, and this forced us to use a mast in the local retail park which is much further away and out of the screenshot above. This resulted in a signal strength of 16 as opposed to 23 from O2. This is the advantage of using the CLX SIM; it allows the modem to choose the most reliable network.
Another advantage of using the CLX SIM is that the GSM device will come with the APN set up correctly by default. The Access Point Name (APN) tells the network which server your equipment can use. Networks will have different APN for different customers like PAYG or contract. If you select the wrong one you will have no data access. This is the main cause of issues when using our software and emails. Our boards come with the APN settings for CLX pre-programmed which can be used globally.
To demonstrate data connectivity with the CLX SIM cards we will make use of Quectel’s Cellular Positioning System. This will give is the geographic co-ordinates of the PCB even when indoors. The modem connects, through the internet, to Quectel’s database of GSM masts and then compares the signal strength from each mast to locate the device.
Firstly we must tell the modem the APN which will give us access to the internet as follows:
at+qicsgp=1,”connect”,””,”” …the CLX APN is “connect” with no username or password
at+qcellloc=1 …enquire about our current location
The at+qcellloc command returns our co-ordinates which we can then paste into Google Maps
The position given by the Quec Locate server is about 0.5 miles out with our high gain antenna. This is towards a worst case scenario situation given that our PCB is buried deep within a building. If it were outside it would be much more accurate.
We tried again using the internal adhesive antenna we use for our Gold:Mini Intercom and this time the error was about 0.8 miles. This is because the internal antenna is optimised for 1800MHz masts which are predominantly located in this direction.
To view our GSM products and for live demonstrations please visit our stand at IFSEC 2018. We look forward to meeting you.
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.
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.
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.
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!
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.
For further reading please see:
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.
Our software allows you to change your dialler and intercom settings, numbers and messages remotely using the internet. It requires a small amount of data allowance to be available on your SIM. A session will use a couple of kB.
v1.07 will work with any firmware release from 5.10 onwards. We can remotely update your dialler and intercom with the latest firmware if required (you must have at least v5.10 to start with).
The software is available from our Downloads page:
Please note currently we do not require installation of the software which is available as a raw EXE file. If you download this from our website you can trust it. You may need to click ‘run anyway’ on the Windows security message box. We will release an installation version over the next few weeks.
We have a simpler wiring diagram for basic connection available here. The above diagram allows for controlling the alarm via your phone and monitoring it’s status. To power the GSM Dialer you can use the auxiliary output on your Texecom panel. The positive (+) terminal is connected to one of the VIN terminals (the lower one is best as it has on-board thermal fuse protection) and the negative (-) terminal to GND on the GSM Dialer PCB. You then connect the BELL terminal to input A.
For switching the alarm on and off you wire the output relay to zone 8 using the NC&COM terminals (either way around). To monitor the status of the alarm you connect the SW terminal to input B.
To program the dialer the following commands are sent:
master <your number>. This gives you control of the dialler
callnuma <number 1 etc…>. This sets the numbers to call when the alarm sounds
textnum <numbers>. This sets the numbers to text when the alarm sounds or is set
textnuma <numbers>. This is just for when the alarm sounds (a)
textnumb <numbers>. This would be just for when the alarm is set/unset (b)
To get a message when the alarms starts and stops send:
To get a message when the alarm is set and unset:
To program the Veritas Panel zone 8 must be set as a key-switch input:
From the Programming Menu, press # followed by the
zone number (8). The Zone Type currently selected will
indicate i.e. Entry/Exit.
Press the Zone Type number required – in this case 8 (keyswitch). Press PROG.
The system will chime to confirm the new Zone Type has
The defaults settings will be correct for the SW output.
The GSM Dialler is available from our online shop here