Thanks. Actually, I've never thought to check my Oppo packaging for a dongle, as I usually make sure there is nothing left in the box when I install a piece of gear. But I have just checked and there definitely isn't one in the box. If you say there should have been one, perhaps it was accidentally left out. Can I use any dongle? (I don't have one, but could of course get one).
I would suggest you either move the machine nearby your router and connect there with Ethernet, or just buy a long Ethernet cable that can reach the player's current position, and that could be used temporarily when ripping and picked up when not in actual use.
Yes there is definitely a USB -> WiFi dongle included with the Oppo 10x series players, and while other WiFi dongles might also work, I can't tell you which ones or guarantee anything. Some might very well be incompatible, it comes down to whether or not they support Linux, and possibly which chipset they use and whether or not thats compatible with the 103's firmware.
For example, many such dongles do not work with the Raspberry Pi single board computer, that I know for sure, so it's entirely possible that some also might not work with the 103.
It will only work on the 2.4GHz WiFi band, the 5GHz band will not work, so if your router has both, only try with the 2.4GHz band.
This one reportedly works, I don't know if it's as simple as picking one known to work with Linux, or if it needs to be a specific chipset, but many have claimed it needs to have the MediaTek Ralink RT5370 chip or it won't work. There should be plenty of choices about $10 for that sort of thing, whereas finding an actual Oppo branded replacement will be difficult and run more like $50 which is ridiculous.
Something like this is a known brand, and while it doesn't list the chipset in use, it does say compatible with Linux kernel versions 2.6.18 - 4.4.3, so I'd bet it will work as the 103 runs Linux kernel 2.6.35. That one isn't really a dongle though, no extender cable, not a problem for short range reception but could be an issue if your 103 is hidden away inside of a cabinet or surrounded by other metal chassis components, however you can use an existing USB Type A male/female extender if you have one, or pick up
something like this which will give you a little placement flexibility.
PS - Is it possible your original Oppo dongle is already there connected at the rear of the player and you just forgot about it?