IceLP is shipped with PLUS.
There are 2 parts to it, the client that runs on windows and the daemon that goes on the particular unix server that is specific to the type of unix server being used.
The CD contains the server side program for SCO unix, x86 SVR4 unix (unixware, etc) and x86 linux.
There is a timeout in the windows icelp settings under pcprint that lets you tune the check time. The minimum interval is 1 * 15 seconds.