diff --git a/biju.gemspec b/biju.gemspec
index a4aa2a4..5798961 100644
--- a/biju.gemspec
+++ b/biju.gemspec
@@ -18,4 +18,5 @@ Gem::Specification.new do |gem|
   gem.add_development_dependency "minitest",    "3.0.0"
 
   gem.add_dependency "serialport",              ">=1.0.4"
+  gem.add_dependency "parslet", "~> 1.5.0"
 end
diff --git a/lib/biju/parser.rb b/lib/biju/parser.rb
new file mode 100644
index 0000000..d4210e5
--- /dev/null
+++ b/lib/biju/parser.rb
@@ -0,0 +1,76 @@
+require 'parslet'
+require 'date'
+
+module Biju
+  class ATParser < Parslet::Parser
+    root :at_string
+
+    rule(:at_string) { request | response }
+
+    # REQUEST
+    rule(:request) { str('+++') | str('A/') | (prefix >> match('[^\r]').repeat) }
+    rule(:prefix) { str('AT') | str('at') }
+
+    # RESPONSE
+    rule(:response) { (status | command) >> crlf }
+    rule(:command) { mgl | pms | mserror }
+
+    rule(:mserror) { str('+CMS ERROR').as(:cmd) >> str(': ') >> message }
+    rule(:mgl) do
+      (str('+CMGL').as(:cmd) >> str(': ') >> infos >> crlf >> message).repeat.as(:sms) >>
+      crlf >> status
+    end
+    rule(:pms) do
+      str('+CPMS').as(:cmd) >> str(': ') >> str('(').maybe >> array >> str(')').maybe
+    end
+
+    rule(:array) do
+      (data >> (comma >> data).repeat).as(:array)
+    end
+    rule(:data) { (str('(') >> array >> str(')')) | info }
+    rule(:infos) { (info >> (comma >> info).repeat).as(:infos) }
+    rule(:info) { datetime | string | int | empty_string }
+    rule(:message) { match('[^\r]').repeat.as(:message) >> crlf }
+
+    # MISC
+    rule(:status) { (ok | error).as(:status) }
+    rule(:ok) { str('OK').as(:ok) }
+    rule(:error) { str('ERROR').as(:error) }
+
+    rule(:crlf) { str("\r") }
+    rule(:comma) { str(',') }
+    rule(:quote) { str('"') }
+
+    rule(:empty_string) { str('').as(:empty_string) }
+    rule(:string) { quote >> match('[^\"]').repeat.as(:string) >> quote }
+    rule(:int) { match('[0-9]').repeat(1).as(:int) }
+
+    rule(:datetime) { quote >> (date >> str(',') >> time).as(:datetime) >> quote }
+    rule(:date) do
+      (match('[0-9]').repeat(2) >> str('/')).repeat(2) >> match('[0-9]').repeat(2)
+    end
+    rule(:time) do
+      (match('[0-9]').repeat(2) >> str(':')).repeat(2) >> match('[0-9]').repeat(2) >>
+      str('+') >> match('[0-9]').repeat(2)
+    end
+  end
+
+  class ATTransform < Parslet::Transform
+    rule(cmd: simple(:cmd), infos: subtree(:infos), message: simple(:message)) do
+      {cmd: cmd.to_s, infos: infos, message: message.to_s}
+    end
+    rule(cmd: simple(:cmd), array: subtree(:array)) do
+      {cmd: cmd.to_s, array: array}
+    end
+
+    rule(empty_string: simple(:empty_string)) { '' }
+    rule(int: simple(:int)) { int.to_i }
+    rule(string: simple(:string)) { string.to_s }
+    rule(datetime: simple(:datetime)) { DateTime.strptime(datetime.to_s, "%y/%m/%d,%T") }
+    rule(array: subtree(:array)) { array }
+
+    rule(status: simple(:status)) { { status: status } }
+    rule(ok: simple(:ok)) { true }
+    rule(error: simple(:error)) { false }
+  end
+end