The maximum color depth is determined by the version of Windows Server (NT4 TSE, 2000, or 2003), and whether or not you're using Citrix MetaFrame. The selection of color depth & resolution is determined by the client's Remote Desktop Settings
In Windows 2000 the maximum color depth available via RDP was 256 colors, 16 bit was only attainable by using the ICA Protocol with the addition of Citrix MetaFrame
With Windows Server 2003 w/ RDP Client 5.1+ you can get up to 24 bit color using RDP
Patrick Rous
Microsoft MVP - Terminal Serve
www.workthin.com