I have been in China and trying to use my chip Discover it card. Apparently the POS terminals here will not read Discover's chip. I have to fall back to magnetic stripe in the end.
You will need to (let cashier) insert the card first, and have the terminal say some error messages and prompt you to swipe, then you can fall back to mag stripe transaction. Most probably the terminals only have UnionPay PBOC protocol but not Discover's EMV protocol.
I have only tried my Discover card on terminals that can only process cards through UnionPay network, but not those who can process foreign issued Visa/MC/etc. (in which case I will use my Visa cards instead).