These USB Interfaces provide a solution to the lack of available Serial (COM) ports on laptop and newer desktop computers for controlling your radio. The USB interface III includes full optical isolation of all control signals (radio control, CW, PTT and Squelch) and built-in USB soundcard with front panel level controls for transmit via your transceiver's Accessory audio input and the constant level (pre-volume control) audio output. microHAM USB Interfaces have built-in hardware support for your radio - you no longer need additional level converters like CT-62, IF-232, FIF-232, CT-17. USB Interface III includes support for CW keying (DTR) and PTT (RTS) as well as a detector/driver for pseudo-FSK and QSK CW on the soundcard's right audio channel for use with FLDIGI on any platform. USB Interface III uses same cable as USB Interface II or DIGI KEYER. Package contains: micro USB Interface III™, CD ROM with drivers, control software and manual and USB A-B cable.