The K40CW Board is a companion board for the K40 CW Keyboard Keyer which allows CW decode and display CW on the K40's LCD display. The K40 CW Reader accepts audio from your receiver and provides impressive copy. In order to use the CW Reader the K40 firmware must be upgraded to Rev G. When the K40 powers up it displays the firmware revision of the two PICs, they must both be vG to support the K40 CWR.
We offer a kit of two solid state relays and resistors that you can use to upgrade a WKUSB with optocouplers to solid state relays. If you have either NEC or Toshiba TLP627-2 parts in sockets U1 and U3 (near the RCA jacks) those are optocouplers. Read through the upgrade instructions to see what needs to be done to upgrade your keyer: SSR Upgrade instructions