Some mobile operators are planning to switch off the 2G and 3G networks completely in the course of 2021. In some countries, this is already to be practiced. In Germany, for example, only the 3G network will be discontinued from 2021. The 2G / GSM network will continue to be maintained here. Therefore, it is advisable to contact your local mobile network provider.

The GSM modems from the manufacturer Didactum support the 2G / GSM mobile network. If the 2G mobile network standard is still offered in your country, you do not have to worry too much.

Customers who are planning to implement a server room monitoring solution based on Didactum's product range should ideally choose an LTE modem in the online store.

Yes. Each Didactum monitoring unit equipped with a GSM or LTE modem is able to send so-called "Heartbeat-SMS" messages in periodic intervals to one or more phone numbers. With the support of this "Heatbeat-SMS" function, you and your colleagues are regularly informed whether the measuring and control device is available and working correctly.

Yes. In the built-in logic of the Ethernet-based remote monitoring & control system, you can configure each floating / dry contact individually. In addition to an alarm by e-mail and / or SNMP (Simple Network Management Protocol), this smart device also sends SMS messages to up to 10 different phone numbers. The content of the e-mail or SMS message can be customized by you in the multilingual web interface of the unit.

Yes. Didactum provides a free GSM plugin for the internal modems. This allows Nagios and Zabbix to send important SMS messages and alarms via the built-in GSM modem. An additional SMS gateway is not necessary.

Yes. All current monitoring systems and PDUs from manufacturer Didactum offer telephone support for the integrated GSM and LTE modems. When alarms are triggered, an SMS text message can be sent and an addtional phone number can be called.

If the SMS notification you created is longer than 160 characters, the smart Didactum monitoring system will send two SMS text messages.

Yes. Every IP-based remote measurement and monitoring unit offers extensive macro functions for individualization of notification and alarm messages.

No. The majority of our customers already have existing mobile phone contracts. Simply contact your mobile phone provider and request a SIM card for sending SMS with your Didactum remote monitoring & control device.

Nagios can use the GSM or LTE modem of the monitoring system to send SMS notifications and SMS alerts. Please request the free GSM modem plugin for Nagios from our support.

The "Test" function of the GSM or LTE modem is only used to check whether the remote monitoring unit really sends SMS messages successfully. In order to check the SMS alert function, you must trigger a previously created logic. If no logic has been defined in the web interface under "Logic schemes", the remote monitoring device cannot send any SMS alerts.

To ensure that the correct time is displayed in your SMS alarm message, please make sure that the correct time zone has been set in the web interface of your remote monitoring unit. The time settings can be found under "Preferences" => "Time". The selected time zone must match the time zone of your Internet browser (operating system).

Thank you for sending us your backup.zor config file. After inspection by our support staff, it turned out that you entered your mobile phone number incorrectly. Please always use the country code. Instead of 017112345678 please enter +44752112345678 for Germany. If you use more several mobile phone numbers, please separate them by spaces, comma or semicolon only. Further information on setting up the GSM or LTE modem can be found in the download area of our online shop.

Just get a SIM card adapter. In your case, a "Micro SIM to Standard" adapter. This makes it easy to turn your Micro SIM card into a standard SIM card. If you have a "Nano SIM card ",  simply use a "Nano to Standard" SIM card adapter. 

Important: Please do use strips to fix the SIM card, as the standard SIM card can then no longer insert correctly into the GSM modem.

We regularly test the GSM modems of our remote monitoring unit with SIM cards from leading mobile service providers. Any updated network operator settings will be provided by us in the form of firmware updates. Please insert the SIM card into a mobile phone / smartphone. Check if the mobile card has already been activated. Often the SIM card itself must be activated / unlocked by the user. Then deactivate with your mobile phone the PIN CODE query of the SIM card and plug it back into the GSM modem of the monitoring system. The SMS notifications should then work properly.

First, check if your monitor device is equipped with a GSM modem. The internal GSM modem can be found in the web interface under "System tree".  If your IT monitoring device does not have the GSM option, please order it in our online store. Carefully insert the mini SIM card with the chip facing down into the SIM card slot of the internal GSM modem, i.e. the notch of the mini-SIM card is on the left side. If you have a micro or nano SIM card, please use a suitable SIM card adapter or remove only the mini SIM card from the (SIM) card carrier.

The new generation of IT monitoring systems (Didactum Monitoring System 50 / 100II / 100III (DC) / 400 / 500 II (DC) / 600 / 700 ) offers an integrated "SMS Gate" function. This means that only one Didactum IT monitoring system has to be equipped with a GSM modem. Then the others remote monitoring devices can use the "SMS Gate" for sending SMS notifications and alerts.

Please go into the settings of your GSM modem and change to "Debug" under "Verbosity Level". The IP-based monitoring system then will save the messages in a LOG file. This looks like this:

Network registration


0 – No registration code

1 – Yes have registration code

2 – Yes have registration code  + additional


0 – No registration, no search

1 – have registration, home network

2 – No registration, no search

3 – registration denied

4 – unknown 

5 – roaming

The messages in the LOG file will help you to identify the problems of your SIM card.

Please use a SIM card from a different mobile carrier. Our many years of experience have shown, that the various mobile carriers offer different mobile network coverage. Furthermore, the installation of a weatherproof outdoor antenna is recommended in server room and data center infrastructure. 

Our egineers regularly test the GSM modems of our remote monitoring systems with SIM cards from leading cell phone providers. Updated network operator settings are provided in the form of firmware updates. Please insert your SIM card into a mobile phone / smartphone. Check if your SIM card has already been activated. Often, the SIM card must be manually activated by the user. Then deactivate the pin code of SIM card with your mobile phone and plug it back into the internal GSM modem of your remote monitoring system. The SMS notification should now work properly.

By using a so-called E-Mail to SMS gateway, the e-mail alerts of your remote monitoring device can be sent directly to your mobile phone via SMS. This paid service is offered by serveral cell phone providers. An e-mail to SMS Gateway is set up within minutes. Just contact the hotline of your wireless carrier.

If the number of the short message center (SMS center) was not filled in automatically in the web interface, please check the documents of your mobile phone provider.

Important note: Please note that in the field "SMS Center Number" the number of the short message center (SMSC) is entered without "+" sign!

Check if the short message center number (SMSC) is correct. Furthermore, there must not be a "+" sign in the "SMS center number" field. If yes, please remove the "+" before the country code.