diff --git a/lib/biju/hayes.rb b/lib/biju/hayes.rb
index cafd8de..3b52111 100644
--- a/lib/biju/hayes.rb
+++ b/lib/biju/hayes.rb
@@ -79,8 +79,12 @@ module Biju
       nil
     end
 
+    def pin_status
+      at_command('+CPIN?')[:result]
+    end
+
     def unlock_pin(pin)
-      at_command('+CPIN', pin)[:status]
+      at_command('+CPIN', pin)[:status] if pin_status == 'SIM PIN'
     end
 
     def messages(which = :all)
diff --git a/lib/biju/parser.rb b/lib/biju/parser.rb
index 1ee4b61..7c9b57e 100644
--- a/lib/biju/parser.rb
+++ b/lib/biju/parser.rb
@@ -17,7 +17,7 @@ module Biju
     # RESPONSE
     rule(:response) { ((command.maybe >> status) | merror) >> crlf | prompt }
     rule(:prompt) { str('> ').as(:prompt) }
-    rule(:command) { mgl | num | pms | mgf | mgs }
+    rule(:command) { mgl | num | pin | pms | mgf | mgs }
 
     rule(:merror) do
       (str('+CME ERROR') | str('+CMS ERROR')).as(:cmd) >> str(': ') >>
@@ -39,6 +39,9 @@ module Biju
     rule(:mgf) do
       str('+CMGF').as(:cmd) >> str(': ') >> boolean.as(:result) >> crlf >> crlf
     end
+    rule(:pin) do
+      str('+CPIN').as(:cmd) >> str(': ') >> eol.as(:result) >> crlf >> crlf
+    end
     rule(:mgs) do
       str('+CMGS').as(:cmd) >> str(': ') >> int.as(:result) >> crlf >> crlf
     end
@@ -66,6 +69,7 @@ module Biju
     rule(:string) { quote >> match('[^\"]').repeat.as(:string) >> quote }
     rule(:int) { match('[0-9]').repeat(1).as(:int) }
     rule(:boolean) { match('[01]').as(:boolean) }
+    rule(:eol) { (crlf.absent? >> any).repeat.as(:string) }
 
     rule(:datetime) { quote >> (date >> str(',') >> time).as(:datetime) >> quote }
     rule(:date) do
diff --git a/spec/biju/parser_spec.rb b/spec/biju/parser_spec.rb
index e20705a..4f7b4ea 100644
--- a/spec/biju/parser_spec.rb
+++ b/spec/biju/parser_spec.rb
@@ -93,6 +93,16 @@ describe Biju::ATParser do
       expect(result[:array]).to eq([23, 23, 7, 100, 7, 100])
     end
 
+    it "gets pin status" do
+      pin = "AT+CPIN?\r\r\n+CPIN: READY\r\n\r\nOK\r\n"
+
+      result = Biju::ATTransform.new.apply(
+        Biju::ATParser.new.parse(pin))
+
+      expect(result).to include(status: true)
+      expect(result[:result]).to eq("READY")
+    end
+
     it "parses +CMGF? response" do
       mgf = "AT+CMGF?\r\r\n+CMGF: 0\r\n\r\nOK\r\n"