SvxLink was created by Tobias (SM0SVX) already around 2002 and is developed since then constantly further. It consists of a main and/or core program and so-called logics, which can be combined quasi arbitrarily. Each logic can be assigned different modules. Echolink is just one of many other modules, so SvxLink differs considerably from the classic Echolink. It is not limited to the operation of a single relay/simplex link, but can theoretically configure and operate any number of relays/links independently of each other. The following figure illustrates the principle.
If the sound card supports it, then the two stereo channels can be used separately, i.e. the left channel controls the 70cm relay, the right channel the 23cm relay and, of course, both independently of each other. In principle, there are two different levels in this application, the core system, which implements the basic functions, and a kind of presentation level, which provides the functionality „outside“. The presentation level is realized by an event handling system implemented in SvxLink. For every possible event, such as opening or closing the squelch, incoming echo link, … a TCL function is called, into which the SvxLink sysop can integrate its own routines. This interface is basically comparable to the VisualBasic extension of EcholinkPlus, but offers much more functionality.