Here is the UDS-10, no power supply, untested...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=380039346277&_trksid=p2759.l1259
I'm getting with the owner to see if she will let me test the Lantronix. I am using a UDS-10 on my Atari 800 as I type this on the G3 Wallstreet. Neat device. If I could convince that person to let me test both, and if both work, offer to sell to you at say $40-$50, and then change the usual $100 for the other...
Could be nice.
Yeh think I need to take my Tandy 100 for a spin on the UDS-10.