Update README (#3)

* Update README

* Update README again

* Fix a few typos

README.md

@@ -1,69 +1,77 @@
-
+# ACARSDEC
-ACARSDEC
-
-Acarsdec is an open source, realtime  ACARS demodulator and position decoder for Linux.
 
 Aircraft Communication Addressing and Reporting System (or ACARS) is a digital datalink system for transmission of small messages between aircraft and ground stations via VHF radio.
 
-HOW DOES IT WORK ?
+Acarsdec is an open source, realtime ACARS demodulator and position decoder for Linux.
 
-To receive ACARS you need at least an AM VHF air band receiver tuned to one of these frequencies :
+## HOW DOES IT WORK ?
 
-131.725	Europe primary
+To receive ACARS you need at least an AM VHF air band receiver tuned to one of these frequencies:
-131.525	European secondary
+
-131.550	USA primary
+- 131.725	Europe primary
-130.025	USA secondary
+- 131.525	European secondary
-131.450 Japan primary
+- 131.550	USA primary
-(these are the most common, google is your friend for other frequencies)
+- 130.025	USA secondary
+- 131.450 Japan primary
+
+(These frequencies are the most common, Google is your friend for other frequencies)
 
 Audio output from this receiver is send to the soundcard input of your PC under Linux.
-Then, acarsdec will demodulate the signals sent by aircrafts and print the received messages on its standart output in airnav log text format.
+Then, acarsdec will demodulate the signals sent by aircraft and print the received messages on its standard output in airnav log text format.
 
-BUILDING IT
+## BUILDING IT
-On a Linux system, you will need libsnd librairy, alsa audio system and gcc/make installed.
+On a Linux system, you will need libsnd library, alsa audio system and gcc/make installed.
-Then just type :
-make
 
-USING IT
+Then just type:
-acarsdec could be called with the following options :
+`make`
-acarsdec [-LR][-s noport] -d alsapcmdevice | -f sndfile 
+
+## USING IT
+acarsdec could be called with the following options:
+```
+acarsdec [-LR][-s noport] -d alsapcmdevice | -f sndfile
  -f sndfile :           decode from file sndfile (ie: a .wav file)
  -d alsapcmdevice :     decode from soundcard input alsapcmdevice (ie: hw:0,0)
- [-LR] :                diseable left or right channel decoding of stereo signal (save cpu)
+ [-LR] :                disable left or right channel decoding of stereo signal (save cpu)
  [-s noport ] :         "xastir" mode : act as an APRS local server, on port : noport (see below)
+```
 
 Input could be mono or stereo but with 48Khz sampling frequency.
-If stereo, acarsdec will demod the 2 channels independantly (if no L ou R options specified)
+If stereo, acarsdec will demod the 2 channels independently (if no L or R options specified)
 
 Typical usage for realtime decoding is :
-acarsdec -d hw:0 
+`acarsdec -d hw:0`
 
 Be sure that correct record level is set for the used soundcard input.
 For testing, you could try to record your receiver output at 48khz sampling frequency with any audio recording tool.
-Save as wav file, then decode it by :
+
-acarsdec -f audiofile.wav.
+Save as wav file, then decode it by:
+`acarsdec -f audiofile.wav`
 
 
-USING IT WITH XASTIR
+## USING IT WITH XASTIR
-acarsdec have a special output mode to use it with APRS position reporting plotting program : xastir (www.xastir.org).
+acarsdec have a special output mode to use it with APRS position reporting plotting program: [xastir](www.xastir.org).
+
 In this mode, acarsdec acts as a very basic local aprsd server.
 ACARS messages, and in particular, position report messages are converted to APRS format, so you can plot aircraft positions on a map.
 
 PS: position decoding is in experimental stage. Mail me if you find errors or lack of position reporting.
 
-start acarsdec with the following option :
+Start acarsdec with the following option:
-acarsdec -d hw:0 -s 14000
+`acarsdec -d hw:0 -s 14000`
+
+Then in xastir, choose: 
+- Interface → Interface Control → Add
+- Select: Internet Server, then Add
+- Set Host at 127.0.0.1, Port 14000, Don't allow transmitting, then OK.
 
-Then in xastir, choose : Interface->Interface Control->Add
-Select : Internet Server, then Add
-Set Host at 127.0.0.1, Port 14000, Don't allow transmitting, then Ok.
 This will add an interface in the Interface Control dialog.
 
 Then select this interface and press start.
-To check that acarsdec send messages to xastir, select View->Incoming traffic
+To check that acarsdec send messages to xastir, select View→Incoming traffic
-ACARS messages look like that in xastir :
+
+ACARS messages look like that in xastir:
+```
 F-XXYZ>ACARS:>Fid:AFXXXX Lbl:Q0
+```
 
 Lots of ACARS messages are messages without position report, so be patient before seeing aircraft plotted on the map.
-
-