[RTTY] USB adapter Interface

[Bill and Pam Leahy]

I am trying to run FSK through a serial/USB high speed adapter (Keyspan USA-19hs). The computer has one serial port which works fine with my W3YY FSK interface and MMTTY. The USB port I am using is comm 3. Using the adapter, it will make comm 3 into comm 13. I can set MMTTY for comm 13 and I get PTT and an FSK output with no diddles (they are turned on in MMTTY). If I use the EXTFSK plugin for MMTTY, I cannot get a comm 13 as it only goes to comm 8. Also I get no output from the adapter with EXTFSK. If I stay with comm 13, I do get output as explained above. I do not believe it is the FSK interface itself as it works fine with the straight serial port comm 1. 
I have also tried to get the adapter to work with Writelog with no results. Works fine with the serial port.
Any ideas?

Bill, K0MP