Catalyst 1900 switches running version 6 or higher, they can be upgraded to
the Enterprise software.
http://www.cisco.com/univercd/cc/td/doc/pcat/ca1900.htm#xtocid3
You'll have to purchase the upgrade from a Cisco reseller or Cisco Sales. the product number is
WS-C19/28EEUG.
If you have older Catalyst 1900 switches running a version 5.x, they can be upgraded to version 5.37. But there is not an
Enterprise software available for these "original" Catalyst 1900s.