Soundcard Interfaces

A sound card interface is used for digital operating modes such as RTTY, PSK-31 and FT-8. The need for such a device results from the different or completely missing grounding of the computer and the radio. This results in potential differences which lead to equalizing currents and these in turn lead to a clearly audible hum on the modulation. A sound card interface breaks the galvanic connection between the computer and the radio and thus prevents equalizing currents and hum.

The sound card interface connects the AF inputs and outputs from the radio to the computer, offers PTT control and usually also a CAT interface (Computer Aided Tuning). The connection to the computer is usually always done via USB. More modern sound card interfaces have their own USB sound card integrated, otherwise the sound card built into the PC is used. An own sound card has many advantages, for example, because settings can be made separately for amateur radio applications. Ideally, the manufacturer of the interface should also offer suitable cables for as many different radios as possible. So you don't have to solder cables yourself. Properly configured, a universal sound card interface works with any software that uses the standard interfaces of a computer.