diff --git a/scsh/fdports1.c b/scsh/fdports1.c
index 669da53..3823310 100644
--- a/scsh/fdports1.c
+++ b/scsh/fdports1.c
@@ -436,7 +436,7 @@ scheme_value read_delim(const char *delims, char *buf, int gobble,
     ** stdio FILE*. Yech.
     */
     if( IsChar(peekc) ) {
-	char c = EXTRACT_CHAR(peekc);
+	unsigned char c = EXTRACT_CHAR(peekc);
 	if( delims[c]  ) {		/* Is c in cset? */
 	    if( gobble ) *PortData_Peek(data) = SCHFALSE;
 	    *nread = 0;