diff --git a/checker.bmp b/checker.bmp
new file mode 100644
index 0000000..6dbddf8
Binary files /dev/null and b/checker.bmp differ
diff --git a/img2dm.py b/img2dm.py
index 774f8d8..f9fee77 100644
--- a/img2dm.py
+++ b/img2dm.py
@@ -3,6 +3,7 @@
 # See LICENSE
 
 from imageio import imread
+import serial
 import sys
 
 def record_run(run_count):
@@ -17,7 +18,8 @@ def record_run(run_count):
     if len(bits):
         compressed.extend(bits)
 
-def append_crc(frame):
+def terminate_frame(frame, repeats):
+    # Compute whole frame's CRC16
     result = 0x8408
     poly = 0x8408
 
@@ -32,6 +34,11 @@ def append_crc(frame):
 
     frame.append(result & 255)
     frame.append((result / 256) & 255)
+    frame.append(repeats & 255)     # This is used internally, it's not part of the transmitted data
+
+def make_raw_frame(cmd):
+    frame = [0x85, PLID[3], PLID[2], PLID[1], PLID[0], cmd]
+    return frame
 
 def make_mcu_frame(cmd):
     frame = [0x85, PLID[3], PLID[2], PLID[1], PLID[0], 0x34, 0x00, 0x00, 0x00, cmd]
@@ -43,7 +50,8 @@ def append_word(frame, value):
 
 def usage():
     print("Usage:")
-    print("img2dm.py image barcode page x y")
+    print("img2dm.py port image barcode page (x y)")
+    print("  port: serial port")
     print("  image: image file")
     print("  barcode: 17-character barcode data")
     print("  page: page number to update (0~15)")
@@ -51,11 +59,13 @@ def usage():
     exit()
 
 arg_count = len(sys.argv)
-if arg_count < 4:
+if arg_count < 5:
     usage()
+    
+ser = serial.Serial(sys.argv[1], 57600, timeout = 5)    # 1s timeout for read
 
 # Open image file
-image = imread(sys.argv[1])
+image = imread(sys.argv[2])
 width = image.shape[1]
 height = image.shape[0]
 if width != 208 or height != 112:
@@ -64,7 +74,7 @@ if width != 208 or height != 112:
 
 # Get PLID
 PLID = [0] * 4
-barcode = sys.argv[2]
+barcode = sys.argv[3]
 if len(barcode) != 17:
     usage()
 id_value = int(barcode[2:7]) + (int(barcode[7:12]) << 16)
@@ -73,17 +83,17 @@ PLID[1] = id_value & 0xFF
 PLID[2] = (id_value >> 24) & 0xFF
 PLID[3] = (id_value >> 16) & 0xFF
 
-page = int(sys.argv[3])
+page = int(sys.argv[4])
 if page < 0 or page > 15:
     print("Page can only be between 0 and 15.")
     exit()
 
-if arg_count > 4:
-    pos_x = int(sys.argv[4])
+if arg_count > 5:
+    pos_x = int(sys.argv[5])
 else:
     pos_x = 0
-if arg_count > 5:
-    pos_y = int(sys.argv[5])
+if arg_count > 6:
+    pos_y = int(sys.argv[6])
 else:
     pos_y = 0
 
@@ -93,6 +103,7 @@ bits = []
 
 size_raw = width * height
 
+# Convert image to 1-bit
 for row in image:
     for rgb in row:
         pixels.append(int(round((0.21 * rgb[0] + 0.72 * rgb[1] + 0.07 * rgb[2]) / 255)))
@@ -106,11 +117,11 @@ compressed.append(run_pixel)
 c = 0
 for pixel in pixels[1:]:
     if pixel == run_pixel:
-        # Add to count
+        # Add to run
         run_count += 1
     else:
+        # Record run
         record_run(run_count)
-
         run_count = 1
         run_pixel = pixel
 
@@ -120,6 +131,7 @@ if run_count > 1:
 
 size_compressed = len(compressed)
 
+# Decide on compression or not
 if size_compressed < size_raw:
     print("Compression ratio: %.1f%%" % (100 - ((size_compressed * 100) / float(size_raw))))
     data = compressed
@@ -129,34 +141,47 @@ else:
     data = pixels
     compression_type = 0
 
-# Pad to multiple of bits_per_frame
+# Pad data to multiple of bits_per_frame
 bits_per_frame = 20 * 8
-padding = bits_per_frame - (len(data) % bits_per_frame)
+data_size = len(data)
+padding = bits_per_frame - (data_size % bits_per_frame)
 for b in range(0, padding):
     data.append(0)
 
-data_size = len(data)
-frame_count = data_size / bits_per_frame
+padded_data_size = len(data)
+frame_count = padded_data_size / bits_per_frame
 
-print("Generating %i frames..." % frame_count)
+print("Generating %i data frames..." % frame_count)
 
 frames = []
 
+# Ping frame
+frame = make_raw_frame(0x97)
+frame.append(0x01)
+frame.append(0x00)
+frame.append(0x00)
+frame.append(0x00)
+for b in range(0, 22):
+    frame.append(0x01)
+terminate_frame(frame, 150)
+frames.append(frame)
+
 # Parameters frame
 frame = make_mcu_frame(0x05)
 byte_count = data_size / 8
 append_word(frame, byte_count)
 frame.append(0x00)
 frame.append(compression_type)
-frame.append(0x01)   # PAGE !
+frame.append(page)
 append_word(frame, width)
 append_word(frame, height)
 append_word(frame, pos_x)
 append_word(frame, pos_y)
 frame.extend([0x00, 0x00, 0x88, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00])
-append_crc(frame)
+terminate_frame(frame, 2)
 frames.append(frame)
 
+# Data frames
 i = 0
 for fr in range(0, frame_count):
     frame = make_mcu_frame(0x20)
@@ -168,12 +193,42 @@ for fr in range(0, frame_count):
             v += data[i + bi]
         frame.append(v)
         i += 8
-    append_crc(frame)
+    terminate_frame(frame, 1)
     frames.append(frame)
 
-f = open("out.txt", "w")    # DEBUG
+# Refresh frame
+frame = make_mcu_frame(0x01)
+for b in range(0, 22):
+    frame.append(0x00)
+terminate_frame(frame, 1)
+frames.append(frame)
 
+# DEBUG
+#f = open("out.txt", "w")
+#for fr in frames:
+#    for b in fr:
+#        f.write(format(b, '02X') + " ")
+#    f.write("\n")
+#exit()
+
+# Send data to IR transmitter
+ser.reset_input_buffer()
+i = 1
 for fr in frames:
-    for b in fr:
-        f.write(format(b, '02X') + " ")
-    f.write("\n")
+    data_size = len(fr) - 1
+    repeats = fr[-1]
+    print("Transmitting frame %u, length %u, repeated %u times." % (i, data_size, repeats))
+
+    ba = bytearray()
+    ba.append(data_size)
+    ba.append(repeats)
+    for b in range(0, len(fr) - 1):
+        ba.append(0x80 + (fr[b] >> 4))
+        ba.append(0x80 + (fr[b] & 15))
+    ser.write(ba)
+    ser.flush()
+    ser.read_until('A')
+    i += 1
+
+ser.close()
+print("Done. Please allow a few seconds for the ESL to refresh.")
diff --git a/pommes.bmp b/pommes.bmp
new file mode 100644
index 0000000..c42f76a
Binary files /dev/null and b/pommes.bmp differ
diff --git a/test.bmp b/test.bmp
new file mode 100644
index 0000000..74cdc87
Binary files /dev/null and b/test.bmp differ