2NVoiceBlue Next® is a device that helps directly interconnect a SIP-supporting VoIP network with GSM networks and can be used for direct connection with a telephone set. The voice mode, i.e. outgoing and incoming calls, is the basic function of the gateway. is equipped with all voice mode functions and 2N VoiceBlue Next®provides the highest user comfort. In addition to voice transmission, 2N VoiceBlue ® enables you to send and receive text messages (SMS). No additional equipment Next(such as an external phone) is needed for normal operation. You can use the web interface or AT commands for all the gateway settings. The programmable parameters are set in such a way that you can make calls the moment you connect the system to the Ethernet, connect an antenna and insert the SIM card.
Interoperability list
https://faq.2n.cz/pages/viewpage.action?pageId=52264991