diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x51_Test.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x51_Test.cs
index e08a175..d270417 100644
--- a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x51_Test.cs
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x51_Test.cs
@@ -22,7 +22,6 @@ namespace JT808.Protocol.Extensions.GPS51.Test
         [Fact]
         public void Serializer()
         {
-#warning ������
             JT808_0x0200 jT808UploadLocationRequest = new JT808_0x0200
             {
                 AlarmFlag = 1,
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x52_Test.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x52_Test.cs
new file mode 100644
index 0000000..5dcdc58
--- /dev/null
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x52_Test.cs
@@ -0,0 +1,68 @@
+using JT808.Protocol.Extensions.GPS51.MessageBody;
+using JT808.Protocol.MessageBody;
+using Microsoft.Extensions.DependencyInjection;
+using System;
+using System.Collections.Generic;
+using Xunit;
+
+namespace JT808.Protocol.Extensions.GPS51.Test
+{
+    public class JT808_0x0200_0x52_Test
+    {
+        JT808Serializer JT808Serializer;
+        public JT808_0x0200_0x52_Test()
+        {
+            ServiceCollection serviceDescriptors = new ServiceCollection();
+            serviceDescriptors.AddJT808Configure()
+                               .AddGPS51Configure();
+
+            IJT808Config jT808Config = serviceDescriptors.BuildServiceProvider().GetRequiredService<IJT808Config>();
+            JT808Serializer = new JT808Serializer(jT808Config);
+        }
+        [Fact]
+        public void Serializer()
+        {
+            JT808_0x0200 jT808UploadLocationRequest = new JT808_0x0200
+            {
+                AlarmFlag = 1,
+                Altitude = 40,
+                GPSTime = DateTime.Parse("2018-07-15 10:10:10"),
+                Lat = 12222222,
+                Lng = 132444444,
+                Speed = 60,
+                Direction = 0,
+                StatusFlag = 2,
+                CustomLocationAttachData = new Dictionary<byte, JT808_0x0200_CustomBodyBase>()
+            };
+            jT808UploadLocationRequest.CustomLocationAttachData.Add(JT808_GPS51_Constants.JT808_0x0200_0x52, new JT808_0x0200_0x52
+            {
+                AttachInfoId = 0x52,
+                AttachInfoLength = 1,
+                  Direction = 2
+            });
+            var hex = JT808Serializer.Serialize<JT808_0x0200>(jT808UploadLocationRequest).ToHexString();
+            Assert.Equal("000000010000000200BA7F0E07E4F11C0028003C0000180715101010520102", hex);
+        }
+
+        [Fact]
+        public void Deserialize()
+        {
+            var jt808_0x0200 = JT808Serializer.Deserialize<JT808_0x0200>("000000010000000200BA7F0E07E4F11C0028003C0000180715101010520102".ToHexBytes());
+            jt808_0x0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0x52, out var value);
+            var jt808_0x0200_0x52 = value as JT808_0x0200_0x52; 
+            Assert.Equal(0x02, jt808_0x0200_0x52.Direction);
+
+        }
+        [Fact]
+        public void Deserialize1()
+        {
+            //gps51 demo
+            var jT808UploadLocationRequest = JT808Serializer.Deserialize<JT808Package>("7e020000470412106280030233000000000000200201d365df072f15d500280000002d21091719155801040002a10f2a0200042b049203a46f520103eb06000100ce0a5730011b31010951080000000000000000ca7e".ToHexBytes());
+            var body0200 = jT808UploadLocationRequest.Bodies as JT808_0x0200;
+            body0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0x52 ,out var value);
+            var jt808_0x0200_0x52 = value as JT808_0x0200_0x52;
+            Assert.Equal(0x03, jt808_0x0200_0x52.Direction);
+            
+        }
+    }
+}
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x54_Test.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x54_Test.cs
new file mode 100644
index 0000000..3d4e524
--- /dev/null
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x54_Test.cs
@@ -0,0 +1,82 @@
+using JT808.Protocol.Extensions.GPS51.MessageBody;
+using JT808.Protocol.MessageBody;
+using Microsoft.Extensions.DependencyInjection;
+using System;
+using System.Collections.Generic;
+using Xunit;
+
+namespace JT808.Protocol.Extensions.GPS51.Test
+{
+    public class JT808_0x0200_0x54_Test
+    {
+        JT808Serializer JT808Serializer;
+        public JT808_0x0200_0x54_Test()
+        {
+            ServiceCollection serviceDescriptors = new ServiceCollection();
+            serviceDescriptors.AddJT808Configure()
+                               .AddGPS51Configure();
+
+            IJT808Config jT808Config = serviceDescriptors.BuildServiceProvider().GetRequiredService<IJT808Config>();
+            JT808Serializer = new JT808Serializer(jT808Config);
+        }
+        [Fact]
+        public void Serializer()
+        {
+            JT808_0x0200 jT808UploadLocationRequest = new JT808_0x0200
+            {
+                AlarmFlag = 1,
+                Altitude = 40,
+                GPSTime = DateTime.Parse("2018-07-15 10:10:10"),
+                Lat = 12222222,
+                Lng = 132444444,
+                Speed = 60,
+                Direction = 0,
+                StatusFlag = 2,
+                CustomLocationAttachData = new Dictionary<byte, JT808_0x0200_CustomBodyBase>()
+            };
+            jT808UploadLocationRequest.CustomLocationAttachData.Add(JT808_GPS51_Constants.JT808_0x0200_0x54, new JT808_0x0200_0x54
+            {
+                AttachInfoId = 0x54,
+                AttachInfoLength = 1,
+                Count = 1,
+                WifiInfos = new List<WifiInfo> {
+                       new WifiInfo{
+                            SingnalStrength=12,
+                             WifiMac="E4FDA120FFF1"
+                       }
+                  }
+            });
+            var hex = JT808Serializer.Serialize<JT808_0x0200>(jT808UploadLocationRequest).ToHexString();
+            Assert.Equal("000000010000000200BA7F0E07E4F11C0028003C0000180715101010540001E4FDA120FFF10C", hex);
+        }
+
+        [Fact]
+        public void Deserialize()
+        {
+            var jt808_0x0200 = JT808Serializer.Deserialize<JT808_0x0200>("000000010000000200BA7F0E07E4F11C0028003C0000180715101010540001E4FDA120FFF10C".ToHexBytes());
+            jt808_0x0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0x54, out var value);
+            var jt808_0x0200_0x54 = value as JT808_0x0200_0x54;
+            Assert.Equal(12, jt808_0x0200_0x54.WifiInfos[0].SingnalStrength);
+            Assert.Equal("E4FDA120FFF1", jt808_0x0200_0x54.WifiInfos[0].WifiMac);
+        }
+        [Fact]
+        public void Deserialize1()
+        {
+            //gps51 demo
+            var jT808UploadLocationRequest = JT808Serializer.Deserialize<JT808Package>("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".ToHexBytes());
+            var body0201 = jT808UploadLocationRequest.Bodies as JT808_0x0201;
+            body0201.Position.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0x54 ,out var value);
+            var jt808_0x0200_0x54 = value as JT808_0x0200_0x54;
+            Assert.Equal(202, jt808_0x0200_0x54.WifiInfos[0].SingnalStrength);
+            Assert.Equal("F092B4A22A39", jt808_0x0200_0x54.WifiInfos[0].WifiMac);
+            Assert.Equal(201, jt808_0x0200_0x54.WifiInfos[1].SingnalStrength);
+            Assert.Equal("70AF6A1CC981", jt808_0x0200_0x54.WifiInfos[1].WifiMac);
+            Assert.Equal(200, jt808_0x0200_0x54.WifiInfos[2].SingnalStrength);
+            Assert.Equal("8CA6DF48CE12", jt808_0x0200_0x54.WifiInfos[2].WifiMac);
+            Assert.Equal(199, jt808_0x0200_0x54.WifiInfos[3].SingnalStrength);
+            Assert.Equal("88403B68E784", jt808_0x0200_0x54.WifiInfos[3].WifiMac);
+            Assert.Equal(196, jt808_0x0200_0x54.WifiInfos[4].SingnalStrength);
+            Assert.Equal("E4FDA120FFF0", jt808_0x0200_0x54.WifiInfos[4].WifiMac);
+        }
+    }
+}
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x58_Test.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x58_Test.cs
new file mode 100644
index 0000000..85acc6f
--- /dev/null
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x58_Test.cs
@@ -0,0 +1,69 @@
+using JT808.Protocol.Extensions.GPS51.MessageBody;
+using JT808.Protocol.MessageBody;
+using Microsoft.Extensions.DependencyInjection;
+using System;
+using System.Collections.Generic;
+using Xunit;
+
+namespace JT808.Protocol.Extensions.GPS51.Test
+{
+    public class JT808_0x0200_0x58_Test
+    {
+        JT808Serializer JT808Serializer;
+        public JT808_0x0200_0x58_Test()
+        {
+            ServiceCollection serviceDescriptors = new ServiceCollection();
+            serviceDescriptors.AddJT808Configure()
+                               .AddGPS51Configure();
+
+            IJT808Config jT808Config = serviceDescriptors.BuildServiceProvider().GetRequiredService<IJT808Config>();
+            JT808Serializer = new JT808Serializer(jT808Config);
+        }
+        [Fact]
+        public void Serializer()
+        {
+            JT808_0x0200 jT808UploadLocationRequest = new JT808_0x0200
+            {
+                AlarmFlag = 1,
+                Altitude = 40,
+                GPSTime = DateTime.Parse("2018-07-15 10:10:10"),
+                Lat = 12222222,
+                Lng = 132444444,
+                Speed = 60,
+                Direction = 0,
+                StatusFlag = 2,
+                CustomLocationAttachData = new Dictionary<byte, JT808_0x0200_CustomBodyBase>()
+            };
+            jT808UploadLocationRequest.CustomLocationAttachData.Add(JT808_GPS51_Constants.JT808_0x0200_0x58, new JT808_0x0200_0x58
+            {
+                AttachInfoId = 0x58,
+                AttachInfoLength = 1, 
+                 Humiditys=new List<ushort> { 
+                    12,34
+                 }
+            });
+            var hex = JT808Serializer.Serialize<JT808_0x0200>(jT808UploadLocationRequest).ToHexString();
+            Assert.Equal("000000010000000200BA7F0E07E4F11C0028003C00001807151010105804000C0022", hex);
+        }
+
+        [Fact]
+        public void Deserialize()
+        {
+            var jt808_0x0200 = JT808Serializer.Deserialize<JT808_0x0200>("000000010000000200BA7F0E07E4F11C0028003C00001807151010105804000C0022".ToHexBytes());
+            jt808_0x0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0x58, out var value);
+            var jt808_0x0200_0x58 = value as JT808_0x0200_0x58; 
+            Assert.Equal(new List<ushort> {12,34 }, jt808_0x0200_0x58.Humiditys.ToArray());
+        }
+        [Fact]
+        public void Deserialize1()
+        {
+            //gps51 demo
+            var jT808UploadLocationRequest = JT808Serializer.Deserialize<JT808Package>("7E0200005B0138916061090003000000000000000301595D5206C8EE4C038E000100001710191146400104000000942504000000005110010001010104010301040103010401045708000000000000000058100285026302700298029A027B02860281520103F300EB7E".ToHexBytes());
+            var body0200 = jT808UploadLocationRequest.Bodies as JT808_0x0200;
+            body0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0x58 ,out var value);
+            var jt808_0x0200_0x58 = value as JT808_0x0200_0x58;
+            //Assert.Equal(0x03, jt808_0x0200_0x58.Direction);
+            Assert.Equal(new List<ushort> { 645, 611, 624, 664, 666, 635, 646, 641 }, jt808_0x0200_0x58.Humiditys.ToArray());
+        }
+    }
+}
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x61_Test.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x61_Test.cs
new file mode 100644
index 0000000..cb2404d
--- /dev/null
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0x61_Test.cs
@@ -0,0 +1,68 @@
+using JT808.Protocol.Extensions.GPS51.MessageBody;
+using JT808.Protocol.MessageBody;
+using Microsoft.Extensions.DependencyInjection;
+using System;
+using System.Collections.Generic;
+using Xunit;
+
+namespace JT808.Protocol.Extensions.GPS51.Test
+{
+    public class JT808_0x0200_0x61_Test
+    {
+        JT808Serializer JT808Serializer;
+        public JT808_0x0200_0x61_Test()
+        {
+            ServiceCollection serviceDescriptors = new ServiceCollection();
+            serviceDescriptors.AddJT808Configure()
+                               .AddGPS51Configure();
+
+            IJT808Config jT808Config = serviceDescriptors.BuildServiceProvider().GetRequiredService<IJT808Config>();
+            JT808Serializer = new JT808Serializer(jT808Config);
+        }
+        [Fact]
+        public void Serializer()
+        {
+            JT808_0x0200 jT808UploadLocationRequest = new JT808_0x0200
+            {
+                AlarmFlag = 1,
+                Altitude = 40,
+                GPSTime = DateTime.Parse("2018-07-15 10:10:10"),
+                Lat = 12222222,
+                Lng = 132444444,
+                Speed = 60,
+                Direction = 0,
+                StatusFlag = 2,
+                CustomLocationAttachData = new Dictionary<byte, JT808_0x0200_CustomBodyBase>()
+            };
+            jT808UploadLocationRequest.CustomLocationAttachData.Add(JT808_GPS51_Constants.JT808_0x0200_0x61, new JT808_0x0200_0x61
+            {
+                AttachInfoId = 0x61,
+                AttachInfoLength = 1,
+                   Volage = 200
+            });
+            var hex = JT808Serializer.Serialize<JT808_0x0200>(jT808UploadLocationRequest).ToHexString();
+            Assert.Equal("000000010000000200BA7F0E07E4F11C0028003C0000180715101010610100C8", hex);
+        }
+
+        [Fact]
+        public void Deserialize()
+        {
+            var jt808_0x0200 = JT808Serializer.Deserialize<JT808_0x0200>("000000010000000200BA7F0E07E4F11C0028003C0000180715101010610100C8".ToHexBytes());
+            jt808_0x0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0x61, out var value);
+            var jt808_0x0200_0x61 = value as JT808_0x0200_0x61; 
+            Assert.Equal(200, jt808_0x0200_0x61.Volage);
+
+        }
+        [Fact]
+        public void Deserialize1()
+        {
+            //gps51 demo
+            var jT808UploadLocationRequest = JT808Serializer.Deserialize<JT808Package>("7e0200002c0138083582460440000000000000000301d37b35063f5e4901a0014a011b210917171126010400000c4530011531010461021d74a27e".ToHexBytes());
+            var body0200 = jT808UploadLocationRequest.Bodies as JT808_0x0200;
+            body0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0x61 ,out var value);
+            var jt808_0x0200_0x61= value as JT808_0x0200_0x61;
+            Assert.Equal(0x1d74, jt808_0x0200_0x61.Volage);
+            
+        }
+    }
+}
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xe1_Test.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xe1_Test.cs
new file mode 100644
index 0000000..8124582
--- /dev/null
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xe1_Test.cs
@@ -0,0 +1,80 @@
+using JT808.Protocol.Extensions.GPS51.MessageBody;
+using JT808.Protocol.MessageBody;
+using Microsoft.Extensions.DependencyInjection;
+using System;
+using System.Collections.Generic;
+using Xunit;
+
+namespace JT808.Protocol.Extensions.GPS51.Test
+{
+    public class JT808_0x0200_0xe1_Test
+    {
+        JT808Serializer JT808Serializer;
+        public JT808_0x0200_0xe1_Test()
+        {
+            ServiceCollection serviceDescriptors = new ServiceCollection();
+            serviceDescriptors.AddJT808Configure()
+                               .AddGPS51Configure();
+
+            IJT808Config jT808Config = serviceDescriptors.BuildServiceProvider().GetRequiredService<IJT808Config>();
+            JT808Serializer = new JT808Serializer(jT808Config);
+        }
+        [Fact]
+        public void Serializer()
+        {
+            JT808_0x0200 jT808UploadLocationRequest = new JT808_0x0200
+            {
+                AlarmFlag = 1,
+                Altitude = 40,
+                GPSTime = DateTime.Parse("2018-07-15 10:10:10"),
+                Lat = 12222222,
+                Lng = 132444444,
+                Speed = 60,
+                Direction = 0,
+                StatusFlag = 2,
+                CustomLocationAttachData = new Dictionary<byte, JT808_0x0200_CustomBodyBase>()
+            };
+            jT808UploadLocationRequest.CustomLocationAttachData.Add(JT808_GPS51_Constants.JT808_0x0200_0xe1, new JT808_0x0200_0xe1
+            {
+                AttachInfoId = 0xe1,
+                AttachInfoLength = 1,
+                MCC = 1,
+                MNC = 2,
+                BaseStations = new List<BaseStation> { 
+                        new BaseStation {
+                            LAC=3,
+                            CI=4,
+                            Signal=5,
+                       }
+                  }
+            });
+            var hex = JT808Serializer.Serialize<JT808_0x0200>(jT808UploadLocationRequest).ToHexString();
+            Assert.Equal("000000010000000200BA7F0E07E4F11C0028003C0000180715101010E10A00010002000300000004", hex);
+        }
+
+        [Fact]
+        public void Deserialize()
+        {
+            var jt808_0x0200 = JT808Serializer.Deserialize<JT808_0x0200>("000000010000000200BA7F0E07E4F11C0028003C0000180715101010E10A00010002000300000004".ToHexBytes());
+            jt808_0x0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0xe1, out var value);
+            var jt808_0x0200_0xe1 = value as JT808_0x0200_0xe1; 
+            Assert.Equal(1, jt808_0x0200_0xe1.MCC);
+            Assert.Equal(2, jt808_0x0200_0xe1.MNC);
+            Assert.Equal(3, jt808_0x0200_0xe1.BaseStations[0].LAC);
+            Assert.Equal<uint>(4, jt808_0x0200_0xe1.BaseStations[0].CI);
+            if (jt808_0x0200_0xe1.BaseStations.Count != 1) {
+                Assert.Equal(5, jt808_0x0200_0xe1.BaseStations[0].Signal);
+            }
+        }
+        [Fact]
+        public void Deserialize1()
+        {
+            //gps51 demo
+            var jT808UploadLocationRequest = JT808Serializer.Deserialize<JT808Package>("7e020000440186070970130dfe0000000000040002019279fa06d5f408001a00000000210917084332e10a01cc0000696a0863a8d0e41701000000000000810e3c756e6b6e6f776e20737369643e3101393f7e".ToHexBytes());
+            var body0200 = jT808UploadLocationRequest.Bodies as JT808_0x0200;
+            body0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0xe1 ,out var value);
+            var jt808_0x0200_0xe1= value as JT808_0x0200_0xe1;
+            Assert.Equal(Newtonsoft.Json.JsonConvert.SerializeObject(jt808_0x0200_0xe1), "{\"AttachInfoId\":225,\"AttachInfoLength\":10,\"MCC\":460,\"MNC\":0,\"BaseStations\":[{\"LAC\":26986,\"CI\":140749008,\"Signal\":0}]}");
+        }
+    }
+}
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xe2_Test.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xe2_Test.cs
new file mode 100644
index 0000000..809d709
--- /dev/null
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xe2_Test.cs
@@ -0,0 +1,68 @@
+using JT808.Protocol.Extensions.GPS51.MessageBody;
+using JT808.Protocol.MessageBody;
+using Microsoft.Extensions.DependencyInjection;
+using System;
+using System.Collections.Generic;
+using Xunit;
+
+namespace JT808.Protocol.Extensions.GPS51.Test
+{
+    public class JT808_0x0200_0xe2_Test
+    {
+        JT808Serializer JT808Serializer;
+        public JT808_0x0200_0xe2_Test()
+        {
+            ServiceCollection serviceDescriptors = new ServiceCollection();
+            serviceDescriptors.AddJT808Configure()
+                               .AddGPS51Configure();
+
+            IJT808Config jT808Config = serviceDescriptors.BuildServiceProvider().GetRequiredService<IJT808Config>();
+            JT808Serializer = new JT808Serializer(jT808Config);
+        }
+        [Fact]
+        public void Serializer()
+        {
+            JT808_0x0200 jT808UploadLocationRequest = new JT808_0x0200
+            {
+                AlarmFlag = 1,
+                Altitude = 40,
+                GPSTime = DateTime.Parse("2018-07-15 10:10:10"),
+                Lat = 12222222,
+                Lng = 132444444,
+                Speed = 60,
+                Direction = 0,
+                StatusFlag = 2,
+                CustomLocationAttachData = new Dictionary<byte, JT808_0x0200_CustomBodyBase>()
+            };
+            jT808UploadLocationRequest.CustomLocationAttachData.Add(JT808_GPS51_Constants.JT808_0x0200_0xe2, new JT808_0x0200_0xe2
+            {
+                AttachInfoId = 0xe2,
+                AttachInfoLength = 1,
+                   Version = "123123"
+            });
+            var hex = JT808Serializer.Serialize<JT808_0x0200>(jT808UploadLocationRequest).ToHexString();
+            Assert.Equal("000000010000000200BA7F0E07E4F11C0028003C0000180715101010E206313233313233", hex);
+        }
+
+        [Fact]
+        public void Deserialize()
+        {
+            var jt808_0x0200 = JT808Serializer.Deserialize<JT808_0x0200>("000000010000000200BA7F0E07E4F11C0028003C0000180715101010E206313233313233".ToHexBytes());
+            jt808_0x0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0xe2, out var value);
+            var jt808_0x0200_0xe2 = value as JT808_0x0200_0xe2; 
+            Assert.Equal("123123", jt808_0x0200_0xe2.Version);
+
+        }
+        [Fact]
+        public void Deserialize1()
+        {
+            //gps51 demo
+            var jT808UploadLocationRequest = JT808Serializer.Deserialize<JT808Package>("7e02004043010000086061575429591701bc00000000000c00030158ae9606c9069600000000006b21091717255901040000000130011931010a610204dce21547423230312d47534d2d32313030312d312e312e31c57e".ToHexBytes());
+            var body0200 = jT808UploadLocationRequest.Bodies as JT808_0x0200;
+            body0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0xe2 ,out var value);
+            var jt808_0x0200_0xe2 = value as JT808_0x0200_0xe2;
+            Assert.Equal("GB201-GSM-21001-1.1.1", jt808_0x0200_0xe2.Version);
+            
+        }
+    }
+}
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xf1_Test.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xf1_Test.cs
new file mode 100644
index 0000000..3215932
--- /dev/null
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xf1_Test.cs
@@ -0,0 +1,68 @@
+using JT808.Protocol.Extensions.GPS51.MessageBody;
+using JT808.Protocol.MessageBody;
+using Microsoft.Extensions.DependencyInjection;
+using System;
+using System.Collections.Generic;
+using Xunit;
+
+namespace JT808.Protocol.Extensions.GPS51.Test
+{
+    public class JT808_0x0200_0xf1_Test
+    {
+        JT808Serializer JT808Serializer;
+        public JT808_0x0200_0xf1_Test()
+        {
+            ServiceCollection serviceDescriptors = new ServiceCollection();
+            serviceDescriptors.AddJT808Configure()
+                               .AddGPS51Configure();
+
+            IJT808Config jT808Config = serviceDescriptors.BuildServiceProvider().GetRequiredService<IJT808Config>();
+            JT808Serializer = new JT808Serializer(jT808Config);
+        }
+        [Fact]
+        public void Serializer()
+        {
+            JT808_0x0200 jT808UploadLocationRequest = new JT808_0x0200
+            {
+                AlarmFlag = 1,
+                Altitude = 40,
+                GPSTime = DateTime.Parse("2018-07-15 10:10:10"),
+                Lat = 12222222,
+                Lng = 132444444,
+                Speed = 60,
+                Direction = 0,
+                StatusFlag = 2,
+                CustomLocationAttachData = new Dictionary<byte, JT808_0x0200_CustomBodyBase>()
+            };
+            jT808UploadLocationRequest.CustomLocationAttachData.Add(JT808_GPS51_Constants.JT808_0x0200_0xf1, new JT808_0x0200_0xf1
+            {
+                AttachInfoId = 0xf1,
+                AttachInfoLength = 1,
+                   ICCID = "123456789"
+            });
+            var hex = JT808Serializer.Serialize<JT808_0x0200>(jT808UploadLocationRequest).ToHexString();
+            Assert.Equal("000000010000000200BA7F0E07E4F11C0028003C0000180715101010F109313233343536373839", hex);
+        }
+
+        [Fact]
+        public void Deserialize()
+        {
+            var jt808_0x0200 = JT808Serializer.Deserialize<JT808_0x0200>("000000010000000200BA7F0E07E4F11C0028003C0000180715101010F109313233343536373839".ToHexBytes());
+            jt808_0x0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0xf1, out var value);
+            var jt808_0x0200_0xf1 = value as JT808_0x0200_0xf1; 
+            Assert.Equal("123456789", jt808_0x0200_0xf1.ICCID);
+
+        }
+        [Fact]
+        public void Deserialize1()
+        {
+            //gps51 demo
+            var jT808UploadLocationRequest = JT808Serializer.Deserialize<JT808Package>("7e0200003e0112036008780002000000000000000202728ebb07228d4e013c0000000021091700003301040003ab262b0400000000f1143839383630343032313032303930393737303032e77e".ToHexBytes());
+            var body0200 = jT808UploadLocationRequest.Bodies as JT808_0x0200;
+            body0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0xf1 ,out var value);
+            var jt808_0x0200_0xf1 = value as JT808_0x0200_0xf1;
+            Assert.Equal("89860402102090977002", jt808_0x0200_0xf1.ICCID);
+            
+        }
+    }
+}
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xf6_Test.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xf6_Test.cs
new file mode 100644
index 0000000..86c5b9b
--- /dev/null
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xf6_Test.cs
@@ -0,0 +1,62 @@
+using JT808.Protocol.Extensions.GPS51.MessageBody;
+using JT808.Protocol.MessageBody;
+using Microsoft.Extensions.DependencyInjection;
+using System;
+using System.Collections.Generic;
+using Xunit;
+
+namespace JT808.Protocol.Extensions.GPS51.Test
+{
+    public class JT808_0x0200_0xf6_Test
+    {
+        JT808Serializer JT808Serializer;
+        public JT808_0x0200_0xf6_Test()
+        {
+            ServiceCollection serviceDescriptors = new ServiceCollection();
+            serviceDescriptors.AddJT808Configure()
+                               .AddGPS51Configure();
+
+            IJT808Config jT808Config = serviceDescriptors.BuildServiceProvider().GetRequiredService<IJT808Config>();
+            JT808Serializer = new JT808Serializer(jT808Config);
+        }
+        [Fact]
+        public void Serializer()
+        {
+            JT808_0x0200 jT808UploadLocationRequest = new JT808_0x0200
+            {
+                AlarmFlag = 1,
+                Altitude = 40,
+                GPSTime = DateTime.Parse("2018-07-15 10:10:10"),
+                Lat = 12222222,
+                Lng = 132444444,
+                Speed = 60,
+                Direction = 0,
+                StatusFlag = 2,
+                CustomLocationAttachData = new Dictionary<byte, JT808_0x0200_CustomBodyBase>()
+            };
+            jT808UploadLocationRequest.CustomLocationAttachData.Add(JT808_GPS51_Constants.JT808_0x0200_0xf6, new JT808_0x0200_0xf6
+            {
+                AttachInfoId = 0xf6,
+                AttachInfoLength = 1,
+                    IMEI = "12345678"
+            });
+            var hex = JT808Serializer.Serialize<JT808_0x0200>(jT808UploadLocationRequest).ToHexString();
+            Assert.Equal("000000010000000200BA7F0E07E4F11C0028003C0000180715101010F6083132333435363738", hex);
+        }
+
+        [Fact]
+        public void Deserialize()
+        {
+            var jt808_0x0200 = JT808Serializer.Deserialize<JT808_0x0200>("000000010000000200BA7F0E07E4F11C0028003C0000180715101010F6083132333435363738".ToHexBytes());
+            jt808_0x0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0xf6, out var value);
+            var jt808_0x0200_0xf6 = value as JT808_0x0200_0xf6; 
+            Assert.Equal("12345678", jt808_0x0200_0xf6.IMEI);
+
+        }
+        [Fact]
+        public void Deserialize1()
+        {
+            //gps51 demo
+        }
+    }
+}
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xfa_Test.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xfa_Test.cs
new file mode 100644
index 0000000..5509f6c
--- /dev/null
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xfa_Test.cs
@@ -0,0 +1,67 @@
+using JT808.Protocol.Extensions.GPS51.MessageBody;
+using JT808.Protocol.MessageBody;
+using Microsoft.Extensions.DependencyInjection;
+using System;
+using System.Collections.Generic;
+using Xunit;
+
+namespace JT808.Protocol.Extensions.GPS51.Test
+{
+    public class JT808_0x0200_0xfa_Test
+    {
+        JT808Serializer JT808Serializer;
+        public JT808_0x0200_0xfa_Test()
+        {
+            ServiceCollection serviceDescriptors = new ServiceCollection();
+            serviceDescriptors.AddJT808Configure()
+                               .AddGPS51Configure();
+
+            IJT808Config jT808Config = serviceDescriptors.BuildServiceProvider().GetRequiredService<IJT808Config>();
+            JT808Serializer = new JT808Serializer(jT808Config);
+        }
+        [Fact]
+        public void Serializer()
+        {
+            JT808_0x0200 jT808UploadLocationRequest = new JT808_0x0200
+            {
+                AlarmFlag = 1,
+                Altitude = 40,
+                GPSTime = DateTime.Parse("2018-07-15 10:10:10"),
+                Lat = 12222222,
+                Lng = 132444444,
+                Speed = 60,
+                Direction = 0,
+                StatusFlag = 2,
+                CustomLocationAttachData = new Dictionary<byte, JT808_0x0200_CustomBodyBase>()
+            };
+            jT808UploadLocationRequest.CustomLocationAttachData.Add(JT808_GPS51_Constants.JT808_0x0200_0xfa, new JT808_0x0200_0xfa
+            {
+                AttachInfoId = 0xfa,
+                AttachInfoLength = 1,
+                    Alarm = 1234
+            });
+            var hex = JT808Serializer.Serialize<JT808_0x0200>(jT808UploadLocationRequest).ToHexString();
+            Assert.Equal("000000010000000200BA7F0E07E4F11C0028003C0000180715101010FA04000004D2", hex);
+        }
+
+        [Fact]
+        public void Deserialize()
+        {
+            var jt808_0x0200 = JT808Serializer.Deserialize<JT808_0x0200>("000000010000000200BA7F0E07E4F11C0028003C0000180715101010FA04000004D2".ToHexBytes());
+            jt808_0x0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0xfa, out var value);
+            var jt808_0x0200_0xfa = value as JT808_0x0200_0xfa; 
+            Assert.Equal(1234u, jt808_0x0200_0xfa.Alarm);
+
+        }
+        [Fact]
+        public void Deserialize1()
+        {
+            //gps51 demo
+            var jT808UploadLocationRequest = JT808Serializer.Deserialize<JT808Package>("7e0200006701300001111100d200010000800c00c101585b2406c96b7000000000000021101117593601040012d6ee0202000003020000140480000005150400000008160400000000170200072504000000002b040000000030011f310100ef0d49249249260049249202221103fa0400000001937e".ToHexBytes());
+            var body0200 = jT808UploadLocationRequest.Bodies as JT808_0x0200;
+            body0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0xfa ,out var value);
+            var jt808_0x0200_0xfa = value as JT808_0x0200_0xfa;
+            Assert.Equal(1u, jt808_0x0200_0xfa.Alarm);
+        }
+    }
+}
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xfb_Test.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xfb_Test.cs
new file mode 100644
index 0000000..9e64a80
--- /dev/null
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51.Test/JT808_0x0200_0xfb_Test.cs
@@ -0,0 +1,72 @@
+using JT808.Protocol.Extensions.GPS51.MessageBody;
+using JT808.Protocol.MessageBody;
+using Microsoft.Extensions.DependencyInjection;
+using System;
+using System.Collections.Generic;
+using Xunit;
+
+namespace JT808.Protocol.Extensions.GPS51.Test
+{
+    public class JT808_0x0200_0xfb_Test
+    {
+        JT808Serializer JT808Serializer;
+        public JT808_0x0200_0xfb_Test()
+        {
+            ServiceCollection serviceDescriptors = new ServiceCollection();
+            serviceDescriptors.AddJT808Configure()
+                               .AddGPS51Configure();
+
+            IJT808Config jT808Config = serviceDescriptors.BuildServiceProvider().GetRequiredService<IJT808Config>();
+            JT808Serializer = new JT808Serializer(jT808Config);
+        }
+        [Fact]
+        public void Serializer()
+        {
+            JT808_0x0200 jT808UploadLocationRequest = new JT808_0x0200
+            {
+                AlarmFlag = 1,
+                Altitude = 40,
+                GPSTime = DateTime.Parse("2018-07-15 10:10:10"),
+                Lat = 12222222,
+                Lng = 132444444,
+                Speed = 60,
+                Direction = 0,
+                StatusFlag = 2,
+                CustomLocationAttachData = new Dictionary<byte, JT808_0x0200_CustomBodyBase>()
+            };
+            jT808UploadLocationRequest.CustomLocationAttachData.Add(JT808_GPS51_Constants.JT808_0x0200_0xfb, new JT808_0x0200_0xfb
+            {
+                AttachInfoId = 0xfb,
+                AttachInfoLength = 1,
+                    Power = 1234,
+                    PowerPercent=90,
+                    Status=3,
+            });
+            var hex = JT808Serializer.Serialize<JT808_0x0200>(jT808UploadLocationRequest).ToHexString();
+            Assert.Equal("000000010000000200BA7F0E07E4F11C0028003C0000180715101010FB045A04D203", hex);
+        }
+
+        [Fact]
+        public void Deserialize()
+        {
+            var jt808_0x0200 = JT808Serializer.Deserialize<JT808_0x0200>("000000010000000200BA7F0E07E4F11C0028003C0000180715101010FB045A04D203".ToHexBytes());
+            jt808_0x0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0xfb, out var value);
+            var jt808_0x0200_0xfb = value as JT808_0x0200_0xfb; 
+            Assert.Equal(1234, jt808_0x0200_0xfb.Power);
+            Assert.Equal(90, jt808_0x0200_0xfb.PowerPercent);
+            Assert.Equal(3, jt808_0x0200_0xfb.Status);
+        }
+        [Fact]
+        public void Deserialize1()
+        {
+            //gps51 demo
+            var jT808UploadLocationRequest = JT808Serializer.Deserialize<JT808Package>("7e0200002f04121051313003940000000000002002015fe78006c325d50013000a00a0210924172909010400029d0f2a0200042b0450680014520103fb045F050701097e".ToHexBytes());
+            var body0200 = jT808UploadLocationRequest.Bodies as JT808_0x0200;
+            body0200.CustomLocationAttachData.TryGetValue(JT808_GPS51_Constants.JT808_0x0200_0xfb ,out var value);
+            var jt808_0x0200_0xfb = value as JT808_0x0200_0xfb;
+            Assert.Equal(0x5F, jt808_0x0200_0xfb.PowerPercent);
+            Assert.Equal(0x0507, jt808_0x0200_0xfb.Power);
+            Assert.Equal(0x01, jt808_0x0200_0xfb.Status);
+        }
+    }
+}
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/JT808.Protocol.Extensions.GPS51.xml b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/JT808.Protocol.Extensions.GPS51.xml
index 2310610..e8b7e5f 100644
--- a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/JT808.Protocol.Extensions.GPS51.xml
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/JT808.Protocol.Extensions.GPS51.xml
@@ -376,6 +376,11 @@
             <param name="value"></param>
             <param name="config"></param>
         </member>
+        <member name="P:JT808.Protocol.Extensions.GPS51.MessageBody.WifiInfo.WifiMac">
+            <summary>
+            wifimac
+            </summary>
+        </member>
         <member name="P:JT808.Protocol.Extensions.GPS51.MessageBody.WifiInfo.SingnalStrength">
             <summary>
             信号轻度
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0x54.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0x54.cs
index f2f8482..1467c36 100644
--- a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0x54.cs
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0x54.cs
@@ -48,12 +48,18 @@ namespace JT808.Protocol.Extensions.GPS51.MessageBody
             value.AttachInfoLength = reader.ReadByte();
             writer.WriteNumber($"[{value.AttachInfoLength.ReadNumber()}]附加信息长度", value.AttachInfoLength);
             value.Count = reader.ReadByte();
+            writer.WriteNumber($"[{value.Count.ReadNumber()}]Wifi数量", value.Count);
+            writer.WriteStartArray();
             for (int i = 0; i < value.Count; i++)
             {
-
-                // writer.WriteString($"[{value.Direction.ReadNumber()}]正反转", "未知");
-
+                writer.WriteStartObject();
+                var wifimac = reader.ReadArray(6).ToArray().ToHexString();
+                writer.WriteString($"[{wifimac}]WifiMac", wifimac);
+                var signalstrength = reader.ReadByte();
+                writer.WriteNumber($"[{signalstrength.ReadNumber()}]信号强度", signalstrength);
+                writer.WriteEndObject();
             }
+            writer.WriteEndArray();
         }
         /// <summary>
         /// 
@@ -67,11 +73,14 @@ namespace JT808.Protocol.Extensions.GPS51.MessageBody
             value.AttachInfoId = reader.ReadByte();
             value.AttachInfoLength = reader.ReadByte();
             value.Count = reader.ReadByte();
+            value.WifiInfos = new List<WifiInfo>();
             for (int i = 0; i < value.Count; i++)
             {
-
-                // 
-
+                value.WifiInfos.Add(new WifiInfo
+                {
+                    WifiMac = reader.ReadArray(6).ToArray().ToHexString(),
+                    SingnalStrength = reader.ReadByte()
+                });
             }
             return value;
         }
@@ -84,17 +93,21 @@ namespace JT808.Protocol.Extensions.GPS51.MessageBody
         public override void Serialize(ref JT808MessagePackWriter writer, JT808_0x0200_0x54 value, IJT808Config config)
         {
             writer.WriteByte(value.AttachInfoId);
-            writer.WriteByte(1);
+            writer.Skip(1,out int position);
             writer.WriteByte((byte)value.WifiInfos.Count);
             foreach (var wifi in value.WifiInfos)
             {
-
+                writer.WriteArray(wifi.WifiMac.ToHexBytes());
+                writer.WriteByte(wifi.SingnalStrength);
             }
         }
     }
 
     public class WifiInfo {
-
+        /// <summary>
+        /// wifimac
+        /// </summary>
+        public string WifiMac { get; set; }
         /// <summary>
         /// 信号轻度
         /// </summary>
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0x58.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0x58.cs
index 560fec4..2a0f4c6 100644
--- a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0x58.cs
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0x58.cs
@@ -45,7 +45,7 @@ namespace JT808.Protocol.Extensions.GPS51.MessageBody
             writer.WriteNumber($"[{value.AttachInfoLength.ReadNumber()}]附加信息长度", value.AttachInfoLength);
             writer.WriteNumber($"[{reader.ReadContent(value.AttachInfoLength).ToArray().ToHexString()}]湿度列表", value.AttachInfoLength / 2);
             writer.WriteStartArray();
-            while (reader.ReadCurrentRemainContentLength() > 0) { 
+            for (int i = 0; i < value.AttachInfoLength / 2; i++) { 
                 writer.WriteNumber($"[{reader.ReadUInt16().ReadNumber()}]附加信息长度", reader.ReadUInt16());
             }
             writer.WriteStartArray();
@@ -63,7 +63,7 @@ namespace JT808.Protocol.Extensions.GPS51.MessageBody
             value.AttachInfoId = reader.ReadByte();
             value.AttachInfoLength = reader.ReadByte();
             value.Humiditys = new List<ushort>();
-            while (reader.ReadCurrentRemainContentLength() > 0)
+            for (int i = 0; i < value.AttachInfoLength/2; i++)
             {
                 value.Humiditys.Add(reader.ReadUInt16());
             }
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xe1.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xe1.cs
index 8fa3c13..0fad115 100644
--- a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xe1.cs
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xe1.cs
@@ -48,21 +48,27 @@ namespace JT808.Protocol.Extensions.GPS51.MessageBody
             value.AttachInfoId = reader.ReadByte();
             writer.WriteNumber($"[{value.AttachInfoId.ReadNumber()}]附加信息Id", value.AttachInfoId);
             value.AttachInfoLength = reader.ReadByte();
+            int length = value.AttachInfoLength;
             writer.WriteNumber($"[{value.AttachInfoLength.ReadNumber()}]附加信息长度", value.AttachInfoLength);
             value.MCC = reader.ReadUInt16();
+            length = length - 2;
             writer.WriteNumber($"[{value.MCC.ReadNumber()}]国家编码", value.MCC);
             value.MNC=reader.ReadUInt16();
+            length = length - 2;
             writer.WriteNumber($"[{value.MNC.ReadNumber()}]网络编码", value.MNC);
             writer.WriteStartArray("地区编码列表");
-            while (reader.ReadCurrentRemainContentLength() > 0)
+            while (length > 0)
             {
                 var LAC = reader.ReadUInt16();
+                length = length - 2;
                 writer.WriteNumber($"[{LAC.ReadNumber()}]地区编码", LAC);            
                 var CI = reader.ReadUInt32();
+                length = length - 4;
                 writer.WriteNumber($"[{CI.ReadNumber()}]蜂窝 ID", CI);
-                if (reader.ReadCurrentRemainContentLength() > 0)
+                if (length > 0)
                 {
                     var Signal = reader.ReadByte();
+                    length = length - 1;
                     writer.WriteNumber($"[{Signal.ReadNumber()}]信号强度", Signal);
                 }
             }
@@ -80,17 +86,23 @@ namespace JT808.Protocol.Extensions.GPS51.MessageBody
             JT808_0x0200_0xe1 value = new JT808_0x0200_0xe1();
             value.AttachInfoId = reader.ReadByte();
             value.AttachInfoLength = reader.ReadByte();
-            if (value.AttachInfoLength > 0) {
+            int length = value.AttachInfoLength;
+            if (length > 0) {
                 value.MCC = reader.ReadUInt16();
+                length= length - 2;
                 value.MNC = reader.ReadUInt16();
+                length = length - 2;
                 value.BaseStations = new List<BaseStation>();
-                while (reader.ReadCurrentRemainContentLength()> 0)
+                while (length > 0)
                 {
                     BaseStation baseStation = new BaseStation();
                     baseStation.LAC = reader.ReadUInt16();
+                    length = length - 2;
                     baseStation.CI = reader.ReadUInt32();
-                    if (reader.ReadCurrentRemainContentLength() > 0) {
+                    length = length - 4;
+                    if (length > 0) {
                         baseStation.Signal=reader.ReadByte();
+                        length = length - 1;
                     }
                     value.BaseStations.Add(baseStation);
                 }
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xe2.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xe2.cs
index 70dd5d2..9cc7b00 100644
--- a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xe2.cs
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xe2.cs
@@ -44,7 +44,7 @@ namespace JT808.Protocol.Extensions.GPS51.MessageBody
             value.AttachInfoLength = reader.ReadByte();
             writer.WriteNumber($"[{value.AttachInfoLength.ReadNumber()}]附加信息长度", value.AttachInfoLength);
             var version = reader.ReadVirtualArray(value.AttachInfoLength);
-            writer.WriteString($"[{version.ToArray().ToHexString()}]版本号", reader.ReadRemainStringContent());
+            writer.WriteString($"[{version.ToArray().ToHexString()}]版本号", reader.ReadString(value.AttachInfoLength));
         }
         /// <summary>
         /// 
@@ -57,7 +57,7 @@ namespace JT808.Protocol.Extensions.GPS51.MessageBody
             JT808_0x0200_0xe2 value = new JT808_0x0200_0xe2();
             value.AttachInfoId = reader.ReadByte();
             value.AttachInfoLength = reader.ReadByte();
-            value.Version = reader.ReadRemainStringContent();
+            value.Version = reader.ReadString(value.AttachInfoLength);
             return value;
         }
         /// <summary>
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xf1.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xf1.cs
index a094211..3c1f099 100644
--- a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xf1.cs
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xf1.cs
@@ -45,7 +45,7 @@ namespace JT808.Protocol.Extensions.GPS51.MessageBody
             value.AttachInfoLength = reader.ReadByte();
             writer.WriteNumber($"[{value.AttachInfoLength.ReadNumber()}]附加信息长度", value.AttachInfoLength);
             var iccid = reader.ReadVirtualArray(value.AttachInfoLength);
-            writer.WriteString($"[{iccid.ToArray().ToHexString()}]ICCID", reader.ReadRemainStringContent());
+            writer.WriteString($"[{iccid.ToArray().ToHexString()}]ICCID", reader.ReadString(value.AttachInfoLength));
         }
         /// <summary>
         /// 
@@ -58,7 +58,7 @@ namespace JT808.Protocol.Extensions.GPS51.MessageBody
             JT808_0x0200_0xf1 value = new JT808_0x0200_0xf1();
             value.AttachInfoId = reader.ReadByte();
             value.AttachInfoLength = reader.ReadByte();
-            value.ICCID = reader.ReadRemainStringContent();
+            value.ICCID = reader.ReadString(value.AttachInfoLength);
             return value;
         }
         /// <summary>
diff --git a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xf6.cs b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xf6.cs
index 52176c5..20b4c5b 100644
--- a/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xf6.cs
+++ b/src/JT808.Protocol.Extensions/JT808.Protocol.Extensions.GPS51/MessageBody/JT808_0x0200_0xf6.cs
@@ -44,7 +44,7 @@ namespace JT808.Protocol.Extensions.GPS51.MessageBody
             value.AttachInfoLength = reader.ReadByte();
             writer.WriteNumber($"[{value.AttachInfoLength.ReadNumber()}]附加信息长度", value.AttachInfoLength);
             var imei = reader.ReadVirtualArray(value.AttachInfoLength);
-            writer.WriteString($"[{imei.ToArray().ToHexString()}]IMEI", reader.ReadRemainStringContent());
+            writer.WriteString($"[{imei.ToArray().ToHexString()}]IMEI", reader.ReadString(value.AttachInfoLength));
         }
         /// <summary>
         /// 
@@ -57,7 +57,7 @@ namespace JT808.Protocol.Extensions.GPS51.MessageBody
             JT808_0x0200_0xf6 value = new JT808_0x0200_0xf6();
             value.AttachInfoId = reader.ReadByte();
             value.AttachInfoLength = reader.ReadByte();
-            value.IMEI = reader.ReadRemainStringContent();
+            value.IMEI = reader.ReadString(value.AttachInfoLength);
             return value;
         }
         /// <summary>