diff --git a/tools/atrf-rssi/gui.c b/tools/atrf-rssi/gui.c
index 1972b79..35047d9 100644
--- a/tools/atrf-rssi/gui.c
+++ b/tools/atrf-rssi/gui.c
@@ -1,8 +1,8 @@
 /*
  * atrf-rssi/gui.c - Graphical output for atrf-rssi
  *
- * Written 2010 by Werner Almesberger
- * Copyright 2010 Werner Almesberger
+ * Written 2010-2011 by Werner Almesberger
+ * Copyright 2010-2011 Werner Almesberger
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -40,6 +40,8 @@
 #define	BG_RGBA		0x00408080	/* grid background color */
 #define CHAN_RGBA	0xff4040ff	/* channel number color */
 #define	FREQ_RGBA	0x20ff00ff	/* frequency color */
+#define WCHAN_RGBA	0xffff00e0	/* WLAN channel number color */
+#define WLAN_RGBA	0x8080ffff	/* WLAN channel occupancy color */
 
 #define	X_STEP		17	/* grid x step */
 #define	Y_STEP		 2	/* grid y step */
@@ -48,6 +50,19 @@
 #define	X_OFFSET	 7	/* x coordinate of lower left grid corner */
 #define	Y_OFFSET	40	/* y coordinate of lower left grid corner */
 
+#define	X_WLAN_OFFSET	31
+#define	Y_WLAN_OFFSET	15
+
+#define	WLAN_XR		(X_STEP*9.5/5)
+#define	WLAN_YH		6
+
+
+static enum {
+	area_us,
+	area_eu,
+	area_jp,
+} wlan_area = area_us;
+
 
 static struct timeval t0;
 
@@ -95,6 +110,8 @@ static void clear(SDL_Surface *s)
 	x-5+(pos)*6, x-1+(pos)*6, y+8, y+4, y, CHAN_RGBA
 #define	CSMALL(pos) \
 	x-7+(pos)*4, x-5+(pos)*4, y+15, y+13, y+11, FREQ_RGBA
+#define	CWLAN(pos) \
+	x-4+(pos)*5, x-1+(pos)*5, y+6, y+3, y, WCHAN_RGBA
 
 
 static void label_channels(SDL_Surface *s, int sx, int x0, int y0)
@@ -121,6 +138,66 @@ static void label_channels(SDL_Surface *s, int sx, int x0, int y0)
 }
 
 
+static int wlan_channels(void)
+{
+	switch (wlan_area) {
+	case area_us:
+		return 11;
+	case area_eu:
+		return 13;
+	case area_jp:
+		return 14;
+	default:
+		abort();
+	}
+}
+
+
+static int show_wlan_channel(int c)
+{
+	switch (wlan_area) {
+	case area_jp:
+		if (c == 14)
+			return 1;
+		/* fall through */
+	case area_us:
+		return !((c-1) % 5);
+	case area_eu:
+		return !((c-1) % 4);
+	default:
+		abort();
+	}
+}
+
+
+static void label_wlan_channels(SDL_Surface *s, int sx, int x0, int y0)
+{
+	int x, xb, y, i, c;
+
+	xb = x0;
+	y = s->h-y0+4;
+	for (i = 0; i != wlan_channels(); i++) {
+		c = i+1;
+		/* Japan special channel: 22 MHz from channel 13 */
+		if (c == 14)
+			xb += X_STEP*12/5-X_STEP;
+		if (c > 9) {
+			x = xb;
+			digit(s, c/10, CWLAN(0));
+		} else {
+			x = xb-3;
+		}
+		digit(s, c % 10, CWLAN(1));
+		if (show_wlan_channel(c)) {
+			hlineColor(s, xb-WLAN_XR, xb+WLAN_XR, y-WLAN_YH,
+			    WLAN_RGBA);	
+			vlineColor(s, xb, y-2, y-WLAN_YH+1, WLAN_RGBA);	
+		}
+		xb += sx;
+	}
+}
+
+
 void gui(struct atrf_dsc *dsc)
 {
 	SDL_Surface *surf;
@@ -143,10 +220,31 @@ void gui(struct atrf_dsc *dsc)
 	}
 
 	while (1) {
-		while (SDL_PollEvent(&event))
-			if (event.type == SDL_KEYDOWN ||
-			    event.type == SDL_QUIT)
+		while (SDL_PollEvent(&event)) {
+			switch (event.type) {
+			case SDL_KEYDOWN:
+				switch (event.key.keysym.sym) {
+				case SDLK_j:
+					wlan_area = area_jp;
+					break;
+				case SDLK_e:
+					wlan_area = area_eu;
+					break;
+				case SDLK_u:
+					wlan_area = area_us;
+					break;
+				case SDLK_q:
+					return;
+				default:
+					break;
+				}
+				break;
+			case SDL_QUIT:
 				return;
+			default:
+				break;
+			}
+		}
 
 		shift_grid(z, N_CHAN, N_TIME);
 		sweep(dsc, z);
@@ -159,6 +257,7 @@ void gui(struct atrf_dsc *dsc)
 		    X_OFFSET, Y_OFFSET,
 		    FG_RGBA, BG_RGBA);
 		label_channels(surf, X_STEP, X_OFFSET, Y_OFFSET);
+		label_wlan_channels(surf, X_STEP, X_WLAN_OFFSET, Y_WLAN_OFFSET);
 
 		SDL_UnlockSurface(surf);
 		SDL_UpdateRect(surf, 0, 0, 0, 0);