Didn't see a solution here... or anywhere else. So I thought I would dig this up to say I figured it out!
Same issue... triplite u209-000-r would not work on windows 7 with the built in drivers. Tried what was on the triplite website... same thing.
Then I tried a machine running Windows 8.1 and it freakin works. checked and it's using the file below from 2009
ser2attr64.sys Provider: Tripp Lite File Version: 220.127.116.11 Copyright Copyright(C) Prolific Technology Inc.
So... I used powershell on the windows 8.1 machine to export all of my drivers to a thumb drive
run powershell as admin and type: Export-WindowsDriver -Online -Destination y:\Drivers (or whatever your USB drive destination is)
Then I popped the drive into the win7 machine. Went into the device manager... selected the broken device. Update driver. and pointed it to y:\drivers\set2attr.inf_amd64_dfdc92blablabla
Driver found... installing... and we're in business.
I checked uncle google and found that exact driver here. http://www.driverscape.com/files/share/e654202344f4c20f831784ab8241f2f7.zip