Still don't know what causes the unstability at the higher speed. This repository is for owners of Portmasters. If you need instruction on how to use these strings, you should consult another source. I apologize to everyone else for this entry. This repository has been a tremendous resource to me and my fellow techs.
Most strings here are fairly general anyway.
If this gets too cluttered with nonsense then it reduces it's functionality and becomes less useful to those of us that need it. Now I'm as guilty as you are for posting useless info. If I were you I would go buy a modem that is widely supported. 14400 fax internal. I have used this countless times.