It is a device capturing and controling all the signals, which are being created by the whole system, especially the made and received phone call signals. The device is mostly used for connecting regular phone system with the Internet and backwards.
Snom One plus
Snom ONE plus is a telephone system (PBX), based on SIP protocol, designed as a universal hardware solution, which includes various options for connecting to PSTN: using analog, PRI (E1, T1, J1), BRI ports. When used with the Snom IP-phone it is a reliable and easy to install solution.