Epson UB-E04 Ethernet interface card. This card provides network connectivity to compatible Epson point-of-sale (POS) and impact printers. 
Key features of the UB-E04 Ethernet interface card:
Function It allows an Epson printer to connect to a wired local area network (LAN) using an Ethernet cable.
Connectivity It typically features an RJ-45 Ethernet port.
Compatibility It is compatible with various Epson printer models, particularly POS printers like those in the TM series (e.g., TM-T88V, TM-U220).