I have some dos driven software made by Cochran Undersea Technologies. Basically, the software was written on an x286 or x386 platforms and communicates thru a serial port adapter also made by Cochran. The Windows driven version of dosbox connects and works great on an iMac with dual partitions but I'm having to use a usb serial port adapter on Cochran's adapter. However, I would like to use the natively driven mac version of dosbox to communicate with the usb serial port adapter & Cochran's, but I keep getting "Cannot open com5, systems error 9. The only serial command that works is serial2=dummy which does not work since the mac computer has to communicate with the dive computer. I've tried various serial commands that specify baud rate, stop bits, parity, and bytesize. To no avail, no luck. I can see the usb to RS232 serial port adapter in the mac system information page; and I can see address and something that looks like com port 5. However, the mac OS Yosemite does not say that its com5. It just lists it as 5.

Any suggestions?