DEC's, oops, I mean Compaq's line of text terminals. The VT400 had many important new features not present in other terminals, such as multisession support, and compatibility mode for VT100 capable hosts. If you HAVE to use a text terminal I'd recommend the VT400, but make sure to nab a keyboard from the VT320 series. (The ones on the 400 line are really fragile and uncomfortable). As of 2000, I believe Compaq sold off the terminal business to another company. Instead of selling you a terminal to access that mainframe, they'll now sell you a Windows NT workstation.