Peplink was kind enough to allow the use of Ethernet dongles on the SOHO and certain of the Balance series – as explained here:
It would be helpful if this capability could be extended to the B20 product. We have several installations where this model is used in critical, but low data rate, applications. The B20 is perfect – all we need is one more Ethernet WAN port.
This would allow the customer to use a 4G wi-fi-only device (i.e., one w/o Ethernet) as a WAN. (Example: ZTE Warp Connect with a wi-fi to Ethernet adapter (e.g., something like https://www.amazon.com/gp/product/B004UAKCS6/ref=oh_aui_search_detailpage?ie=UTF8&psc=1) to “turn” 4G into Ethernet.