I recently purchased this Sabrentt FTDI USB to Serial converter to use with my K3 when I got a new PC without an RS-232 port, It works fine: Sabrent USB 2.0 to Serial (9-Pin) DB-9 RS-232 Adapter Cable 6ft Cable (FTDI Chipset). <https://www.amazon.com/gp/product/B006AA04K0/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1> Price was $14.99. Phil N3ZP