diff --git a/drl2gp/drl2gp.c b/drl2gp/drl2gp.c
index 99eedaa..4f43fc3 100644
--- a/drl2gp/drl2gp.c
+++ b/drl2gp/drl2gp.c
@@ -47,21 +47,21 @@ static double depth, d0, d1;
 #define	MIL2MM(mil)	IN2MM((mil)/1000)
 
 
-/*
- * @@@ should at least detect INCH/METRIC
- */
-
 static void header(void)
 {
 	enum {
 		ts_nl,		/* at beginning of line */
 		ts_t,		/* seen a ^T */
+		ts_metric,	/* parsing METRIC,... */
+		ts_inch,	/* parsing INCH,... */
 		ts_tc,		/* seen ^T\d+C */
 		ts_skip,	/* skip to next \n */
 	} state = ts_nl;
 	int c, tool;
 	double f = 1;
 	double tmp;
+	const char *next = NULL;
+	int metric = 1;
 
 	while ((c = getchar()) != EOF) {
 		if (out) {
@@ -77,6 +77,14 @@ static void header(void)
 				state = ts_t;
 				tool = 0;
 				break;
+			case 'I':
+				state = ts_inch;
+				next = "NCH";
+				break;
+			case 'M':
+				state = ts_metric;
+				next = "ETRIC";
+				break;
 			case '%':
 				return;
 			case '\n':
@@ -87,6 +95,24 @@ static void header(void)
 				break;
 			}
 			break;
+		case ts_inch:
+			if (c == ',')
+				metric = 0;
+			else {
+				if (c == *next++)
+					break;
+			}
+			state = ts_skip;
+			break;
+		case ts_metric:
+			if (c == ',')
+				metric = 1;
+			else {
+				if (c == *next++)
+					break;
+			}
+			state = ts_skip;
+			break;
 		case ts_t:
 			if (isdigit(c))
 				tool = tool*10+c-'0';
@@ -108,7 +134,8 @@ static void header(void)
 		case ts_tc:
 			if (isdigit(c)) {
 				tmp = c-'0';
-				tmp = IN2MM(tmp);
+				if (!metric)
+					tmp = IN2MM(tmp);
 				if (f == 1)
 					tool_d[tool] =
 					    tool_d[tool]*10+tmp;
@@ -260,12 +287,10 @@ static void do_cmd(char cmd, double v, int nl)
 			exit(1);
 		}
 		d = tool_d[n];
-fprintf(stderr, "T%d -> %f\n", n, d);
 		if (mill)
 			active = d >= d0;
 		else
 			active = d >= d0 && d <= d1;
-fprintf(stderr, "%g %g %g -> %d\n", d, d0, d1, active);
 		break;
 	case 'X':
 		x = metric ? v : IN2MM(v);