... , DELPHI, PB, C++ Builder,. NET, WEB GXUSB-8-line telephone voice boxFeatures and Benefits: With USB interface, easy to install, plug ... into backplane so it is not easy to loose, the voice board is equipped with ringing current power supply Modules for ... selection of audio encoding, including the A-LAW PCM, ADPCM, GSM, G.729 and so on, volume can be adjusted by ...