I don't remember what I was using at the time, but there's a variety of ways to do it, depending on what you're looking for. Generally, you want to capture network traffic at the packet level and run it through a tool to help you analyze it. The tool you pick would depend on what you're looking for and the type of analysis you're doing. Here's a few tools that come to mind:
Not the original parent commenter but a sniffer like Wireshark would reveal the url(s) or IP addresses being requested by the phone to call home - it’s fairly easy to check if those belong to a Chinese IP range.