diff --git a/BIN/CAT.S.txt b/BIN/CAT.S.txt
index dc860dde..0b52eb23 100644
--- a/BIN/CAT.S.txt
+++ b/BIN/CAT.S.txt
@@ -21,7 +21,7 @@ ArgCount                .BS 1
 FileCount               .BS 1
 bPause                  .BS 1
 bDummy                  .BS 1
-bStdout                 .BS 1
+bIsTTY                  .BS 1
 ArgIndex                .BS 1
 hBuf                    .BS 1
 hFile                   .BS 1
@@ -56,7 +56,7 @@ CS.INIT                         clc
                                 rts
 *--------------------------------------
 CS.RUN                  
-.1                              stz bStdout
+.1                              stz bIsTTY
                    
                                 inc ArgCount
                                 lda ArgCount
@@ -124,8 +124,7 @@ CS.RUN
                                 cmp #S.FD.T.PIPE
                                 beq CS.RUN.LOOP
 
-                                lda #$ff
-                                sta bStdout
+                                inc bIsTTY
                         
                                 >PUSHW L.MSG.INIT
                                 >PUSHBI 0
@@ -186,7 +185,7 @@ CS.RUN.LOOP                     ldy #S.PS.hStdIn
                                 cmp #C.CR
                                 bne CS.RUN.LOOP
 
-                                lda bStdout
+                                lda bIsTTY
                                 beq CS.RUN.LOOP
 
                                 lda #C.LF