The real problem is not setting expectations. When a client wants you to integrate something you don't work with you have to tell them it may cost more money. Time and possibly hardware to get your oven? connected.

Then you will find out if they really need the oven online or if they just wanted it connected because it has WiFi.

AV Guy ...You really need that VCR? It's like an extra $2500 in composite to hdmi converters and HDMI distribution.

Client ...Oh...never mind then. We haven't used it in ten years.