Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
Why not design your own vox switching circuit? There isn't a dedicated "vox chip" - I have used just a couple of transistors for this purpose. You have to be aware that a crude sound operated switch will respond to ANY sound that's loud enough for the circuit to detect.
A proper Vox circuit uses stages of audio filtering and noise cancellation techniques to prevent false triggering. The last Vox that I designed for a radio communications manufacturer used three quad op-amps, two FETs, a comparator IC and a bipolar transistor. The circuit is patented, so I can't post it here (it would be too complicated for you to copy, anyway!).