I think we (and you, probably) need a bit more information. It sounds like you're saying the normal GUI app for controlling the signal generator is on a different box than the signal generator. If this is the case, then there must be some kind of protocol across the wire. You should try to find out what this protocol is. If you're lucky, the maker of the signal generator has published this protocol, or maybe it's an open system and the protocol doc is readily available. If so, then writing a perl app to that protocol shouldn't be too hard.