diff --git a/lib/packer.rb b/lib/packer.rb
index b4f3106..e2f61ab 100644
--- a/lib/packer.rb
+++ b/lib/packer.rb
@@ -46,7 +46,6 @@ class Packer
   end
 
   def self.pack_big_int(sign, num)
-    num += 1 if sign == '1'
     num_bits = num.to_s(2)
     first = "1#{sign}#{num_bits[-6..]}"
 
diff --git a/spec/04_packer_spec.rb b/spec/04_packer_spec.rb
index 31a7b46..4ca1ef4 100644
--- a/spec/04_packer_spec.rb
+++ b/spec/04_packer_spec.rb
@@ -48,11 +48,19 @@ describe 'Packer', :packer do
     end
 
     it 'Should pack negative' do
-      expect(Packer.pack_int(-65).map { |e| e.to_s(2).rjust(8, '0') }).to eq(%w[11000001 00000001])
+      expect(Packer.pack_int(-65).map { |e| e.to_s(2).rjust(8, '0') }).to eq(%w[11000000 00000001])
     end
 
     it 'Should pack large numbers' do
       expect(Packer.pack_int(99_999_999_999_999_999)).to eq([191, 131, 255, 147, 246, 194, 215, 232, 88])
     end
+
+    it 'Should pack -128 to 1111 1111 0000 0001 (match tw traffic)' do
+      expect(Packer.pack_int(-128).map { |b| b.to_s(2).rjust(8, '0') }).to eq(%w[11111111 00000001])
+    end
+
+    it 'Should pack -128 to 0xFF 0x01 (match tw traffic)' do
+      expect(Packer.pack_int(-128)).to eq([0xFF, 0x01])
+    end
   end
 end
diff --git a/spec/05_unpacker_spec.rb b/spec/05_unpacker_spec.rb
index 5b3f9ae..e282b52 100644
--- a/spec/05_unpacker_spec.rb
+++ b/spec/05_unpacker_spec.rb
@@ -44,7 +44,7 @@ describe 'Unpacker', :unpacker do
     end
 
     it 'Should pack and unpack and match from 0 to 63' do
-      (0..63).each do |i|
+      64.times do |i|
         u = Unpacker.new(Packer.pack_int(i))
         expect(u.get_int).to eq(i)
       end
@@ -74,14 +74,14 @@ describe 'Unpacker', :unpacker do
     it 'Should pack and unpack and match from -3 to 3' do
       (-3..3).each do |i|
         u = Unpacker.new(Packer.pack_int(i))
-        expect(u.get_int()).to eq(i)
+        expect(u.get_int).to eq(i)
       end
     end
 
     it 'Should pack and unpack and match from -63 to 63' do
       (-63..63).each do |i|
         u = Unpacker.new(Packer.pack_int(i))
-        expect(u.get_int()).to eq(i)
+        expect(u.get_int).to eq(i)
       end
     end
 
@@ -93,18 +93,23 @@ describe 'Unpacker', :unpacker do
 
   context 'Unpack multi byte integers' do
     it 'Should pack and unpack and match from 0 to 128' do
-      (0..128).each do |i|
+      129.times do |i|
         u = Unpacker.new(Packer.pack_int(i))
         expect(u.get_int).to eq(i)
       end
     end
 
-    # it 'Should pack and unpack and match from -128 to 128' do
-    #   (-128..128).each do |i|
-    #     u = Unpacker.new(Packer.pack_int(i))
-    #     expect(u.get_int()).to eq(i)
-    #   end
-    # end
+    it 'Should unpack 0xFF 0x01 to -128 (match tw traffic)' do
+      u = Unpacker.new([0xFF, 0x01])
+      expect(u.get_int).to eq(-128)
+    end
+
+    it 'Should pack and unpack and match from -128 to 128' do
+      (-128..128).each do |i|
+        u = Unpacker.new(Packer.pack_int(i))
+        expect(u.get_int).to eq(i)
+      end
+    end
 
     it 'Should unpack [128, 1] to 64' do
       u = Unpacker.new([128, 1])