In the market, most of the PCM multiplexer’s ring frequency in FXS phone interface is 25HZ, and it is common, and widely used. But in some area like Europe, it also has big demand for 50HZ ring frequency type. TAK communication company now launch this kind of PCM multiplexer which can support 50HZ ring frequency to meet market demand. For more information, please see view : https://www.takfiberoptic.com/50hz-30-ports-phone-pcm-multiplexer-p-168.html