I installed a Serial Gear 4 port serial to USB converter which runs a FTDI chipset. Link: http://www.serialgear.com/4-Port-Serial-USB-USBG-BAY4.html
The device is sturdy, in a metal case that can be screw mounted, and performs well, EXCEPT for generating a 'crazy mouse' when plugged in. It doesn't always cause the problem, but sometimes I have to plug and unplug the USB connector several times to get it working. Best results when plugging in the USB connector are when CE is running, and all the serial devices (AIS, GPS, Auto Pilot) are already running.
Is there a permanent fix?
Larry H Currently cruising SE Alaska