I wrote: - if hidden "wrap" flag is set and in final column and [?7h in effect, <CRLF> - if in final column, set "wrap" flag for next time (otherwise clear it) - write character, advancing cursor unless in final column The plot sickens ... I was starting to feel paranoid and wanted a second opinion. So I replaced the UA9636/UA9639 driver/receiver chips in the VT101 that's been kicking around my basement for 10+ years waiting for me to get around to that. Now it fails VTTEST too, but not the same way as the VT100! (Characters only at the margins in the failing test, but with gaps.) The 132-col tests are all wrong but that's no surprise since the VT101 has no AVO. Some quick experimentation shows that in the VT101, the rules are the same as the VT100 ones above as long as the cursor doesn't leave the line where a char was written to column 80 for the first time. But if it does (by any means -- DCA, ESC M, <LF>, ESC [B etc.) then the "wrap" flag is cleared, whether a printing character is displayed on the other line or not. OK so DEC's *own* VT100 knockoff isn't even VT100-compatible. Nap time! John Wilson D Bit