This product is either discontinued or we cannot get that from suppliers.
OKI 44455103 Rs232c Serial Interface For Dot Matrix, Designed specially, Compatible with: Oki 320P,Oki 320T,Oki 321P,Oki 390P,Oki 720P,Oki 721P,Oki 790P,Oki 791P.
This Original Genuine OKI Serial RS232C Card Interface is designed specially by OKI for use in the following models OKI 320P, 320T, 321P, 390P, 720P, 721P, 790P & 791P printers & multifunction devices.