I could find no precompiled driver that worked. However, I found GNU-GPL code for one that works nicely on the Point Clark Networks' site. The instructions are for ClearOS 5.4 which is similar to RHEL/Centos.
Roll your own driver with instructions and vt1211.c code at
http://www.grassmere-productions.pointclark.net/vt1211/vt1211.txt
Install kernel-devel and start at Paragraph #3.
Works nice on my little M10000 mini-itx epia box. Until elrepo or Redhat or Centos supports a vt1211.ko for RHEL/Centos 5.4, you will have the privilege of recompiling and reinstalling it every time you update the kernel ( about a 3 minute adventure ).
regards,
benm