Cheap/expensive ones of any make can be hit and miss.

This Keyspan generally gets good reviews

http://www.expansys.com/keyspan-high...dapter-121827/

Although with my DTA, I currently use a £5 egay convertor which looks a lot like this

http://www.amazon.co.uk/Serial-RS232...775563&sr=1-15

They will be a gamble though.

Ive found the PCMCIA to serial converters more reliable though as far as compatibility goes.