diff --git a/README.md b/README.md
index a612059..777e622 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 ## 1. 简介 ##
 
-AT device 软件包是由 RT-Thread AT 组件针对不同 AT 设备的移植文件和示例代码组成，目前支持的 AT 设备有：ESP8266、ESP32、M26、MC20、RW007、MW31、SIM800C、W60X 以及 SIM76XX 系列设备等，目前上述设备都完成对 `AT socket` 功能的移植，及设备通过 AT 命令实现标准 socket 编程接口，完成 socket 通讯的功能，具体功能介绍可参考 [《RT-Thread 编程指南》](https://www.rt-thread.org/document/site/programming-manual/at/at/)AT 命令章节 。 
+AT device 软件包是由 RT-Thread AT 组件针对不同 AT 设备的移植文件和示例代码组成，目前支持的 AT 设备有：A9/A9G、ESP8266、ESP32、M26、MC20、RW007、MW31、SIM800C、W60X 以及 SIM76XX 系列设备等，目前上述设备都完成对 `AT socket` 功能的移植，及设备通过 AT 命令实现标准 socket 编程接口，完成 socket 通讯的功能，具体功能介绍可参考 [《RT-Thread 编程指南》](https://www.rt-thread.org/document/site/programming-manual/at/at/)AT 命令章节 。 
 
 ### 1.1. 目录结构 ###
 
@@ -12,6 +12,7 @@ AT device 软件包是由 RT-Thread AT 组件针对不同 AT 设备的移植文
 | inc | AT device 头文件目录 |
 | sample | 不同设备示例文件目录 |
 | class | 不同设备针对 AT 组件的移植适配目录 |
+| class/a9g | A9G 设备针对 AT 组件的移植目录，实现 AT Socket 功能 |
 | class/esp8266 | ESP8266 设备针对 AT 组件的移植目录，实现 AT Socket 功能 |
 | class/esp32   | ESP32 设备针对 AT 组件的移植目录，实现 AT Socket 功能 |
 | class/rw007 | RW007 设备针对 AT 组件的移植目录，实现 AT Socket 功能 |
diff --git a/SConscript b/SConscript
index 8bcf013..a566f99 100644
--- a/SConscript
+++ b/SConscript
@@ -4,6 +4,15 @@ cwd = GetCurrentDir()
 path = [cwd + '/inc']
 src  = Glob('src/*.c')
 
+# A9G
+if GetDepend(['AT_DEVICE_USING_A9G']):
+    path += [cwd + '/class/a9g']
+    src += Glob('class/a9g/at_device_a9g.c')
+    if GetDepend(['AT_USING_SOCKET']):
+        src += Glob('class/a9g/at_socket_a9g.c')
+    if GetDepend(['AT_DEVICE_A9G_SAMPLE']):
+        src += Glob('samples/at_sample_a9g.c')
+
 # M26/MC20
 if GetDepend(['AT_DEVICE_USING_M26']):
     path += [cwd + '/class/m26']
diff --git a/class/a9g/at_device_a9g.c b/class/a9g/at_device_a9g.c
new file mode 100644
index 0000000..685b57a
--- /dev/null
+++ b/class/a9g/at_device_a9g.c
@@ -0,0 +1,923 @@
+/*
+ * File      : at_socket_a9g.c
+ * This file is part of RT-Thread RTOS
+ * COPYRIGHT (C) 2006 - 2018, RT-Thread Development Team
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2019-11-23     luliang    first version
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+
+#include <at_device_a9g.h>
+
+#define LOG_TAG                    "at.dev.a9g"
+#include <at_log.h>
+ 
+#ifdef AT_DEVICE_USING_A9G
+
+#define A9G_WAIT_CONNECT_TIME      5000
+#define A9G_THREAD_STACK_SIZE      2048
+#define A9G_THREAD_PRIORITY        (RT_THREAD_PRIORITY_MAX/2)
+
+/* AT+CSTT command default*/
+static char *CSTT_CHINA_MOBILE  = "AT+CSTT=\"CMNET\"";
+static char *CSTT_CHINA_UNICOM  = "AT+CSTT=\"UNINET\"";
+static char *CSTT_CHINA_TELECOM = "AT+CSTT=\"CTNET\"";
+
+static void a9g_power_on(struct at_device *device)
+{
+    struct at_device_a9g *a9g = RT_NULL;
+
+    a9g = (struct at_device_a9g *) device->user_data;
+
+    /* not nead to set pin configuration for m26 device power on */
+    if (a9g->power_pin == -1 || a9g->power_status_pin == -1)
+    {
+        return;
+    }
+
+    if (rt_pin_read(a9g->power_status_pin) == PIN_HIGH)
+    {
+        return;
+    }
+    rt_pin_write(a9g->power_pin, PIN_HIGH);
+
+    while (rt_pin_read(a9g->power_status_pin) == PIN_LOW)
+    {
+        rt_thread_mdelay(10);
+    }
+    rt_pin_write(a9g->power_pin, PIN_LOW);
+}
+
+static void a9g_power_off(struct at_device *device)
+{
+    struct at_device_a9g *a9g = RT_NULL;
+
+    a9g = (struct at_device_a9g *) device->user_data;
+
+    /* not nead to set pin configuration for m26 device power on */
+    if (a9g->power_pin == -1 || a9g->power_status_pin == -1)
+    {
+        return;
+    }
+
+    if (rt_pin_read(a9g->power_status_pin) == PIN_LOW)
+    {
+        return;
+    }
+    rt_pin_write(a9g->power_pin, PIN_HIGH);
+
+    while (rt_pin_read(a9g->power_status_pin) == PIN_HIGH)
+    {
+        rt_thread_mdelay(10);
+    }
+    rt_pin_write(a9g->power_pin, PIN_LOW);
+}
+
+
+/* =============================  a9g network interface operations ============================= */
+
+/* set a9g network interface device status and address information */
+static int a9g_netdev_set_info(struct netdev *netdev)
+{
+#define A9G_IEMI_RESP_SIZE      32
+#define A9G_IPADDR_RESP_SIZE    32
+#define A9G_DNS_RESP_SIZE       96
+#define A9G_INFO_RESP_TIMO      rt_tick_from_millisecond(300)
+
+    int result = RT_EOK;
+    ip_addr_t addr;
+    at_response_t resp = RT_NULL;
+    struct at_device *device = RT_NULL;
+	
+    RT_ASSERT(netdev);
+
+    device = at_device_get_by_name(AT_DEVICE_NAMETYPE_NETDEV, netdev->name);
+    if (device == RT_NULL)
+    {
+        LOG_E("get device(%s) failed.", netdev->name);
+        return -RT_ERROR;
+    }
+
+    /* set network interface device status */
+    netdev_low_level_set_status(netdev, RT_TRUE);
+    netdev_low_level_set_link_status(netdev, RT_TRUE);
+    netdev_low_level_set_dhcp_status(netdev, RT_TRUE);
+
+    resp = at_create_resp(A9G_IEMI_RESP_SIZE, 0, A9G_INFO_RESP_TIMO);
+    if (resp == RT_NULL)
+    {
+        LOG_E("no memory for resp create.");
+        result = -RT_ENOMEM;
+        goto __exit;
+    }
+
+    /* set network interface device hardware address(IEMI) */
+    {
+        #define A9G_NETDEV_HWADDR_LEN   8
+        #define A9G_IEMI_LEN            15
+
+        char iemi[A9G_IEMI_LEN] = {0};
+        int i = 0, j = 0;
+
+        /* send "AT+GSN" commond to get device IEMI */
+        if (at_obj_exec_cmd(device->client, resp, "AT+GSN") < 0)
+        {
+            result = -RT_ERROR;
+            goto __exit;
+        }
+
+        if (at_resp_parse_line_args(resp, 2, "%s", iemi) <= 0)
+        {
+            LOG_E("a9g device(%s) prase \"AT+GSN\" commands resposne data error.", device->name);
+            result = -RT_ERROR;
+            goto __exit;
+        }
+
+        LOG_D("a9g device(%s) IEMI number: %s", device->name, iemi);
+
+        netdev->hwaddr_len = A9G_NETDEV_HWADDR_LEN;
+        /* get hardware address by IEMI */
+        for (i = 0, j = 0; i < A9G_NETDEV_HWADDR_LEN && j < A9G_IEMI_LEN; i++, j += 2)
+        {
+            if (j != A9G_IEMI_LEN - 1)
+            {
+                netdev->hwaddr[i] = (iemi[j] - '0') * 10 + (iemi[j + 1] - '0');
+            }
+            else
+            {
+                netdev->hwaddr[i] = (iemi[j] - '0');
+            }
+        }
+    }
+
+    /* set network interface device IP address */
+    {
+        #define IP_ADDR_SIZE_MAX    16
+        char ipaddr[IP_ADDR_SIZE_MAX] = {0};
+
+        at_resp_set_info(resp, A9G_IPADDR_RESP_SIZE, 2, A9G_INFO_RESP_TIMO);
+		
+        /* send "AT+CIFSR" commond to get IP address */
+        if (at_obj_exec_cmd(device->client, resp, "AT+CIFSR") < 0)
+        {
+            result = -RT_ERROR;
+            goto __exit;
+        }
+
+        if (at_resp_parse_line_args_by_kw(resp, ".", "%s", ipaddr) <= 0)
+        {
+            LOG_E("a9g device(%s) prase \"AT+CIFSR\" commands resposne data error!", device->name);
+            result = -RT_ERROR;
+            goto __exit;
+        }
+
+        LOG_D("a9g device(%s) IP address: %s", device->name, ipaddr);
+
+        /* set network interface address information */
+        inet_aton(ipaddr, &addr);
+        netdev_low_level_set_ipaddr(netdev, &addr);
+    }
+
+    /* set network interface device dns server */
+    {
+        #define DNS_ADDR_SIZE_MAX   16
+        char dns_server1[DNS_ADDR_SIZE_MAX] = {0}, dns_server2[DNS_ADDR_SIZE_MAX] = {0};
+
+        at_resp_set_info(resp, A9G_DNS_RESP_SIZE, 0, A9G_INFO_RESP_TIMO);
+
+        /* send "AT+CDNSCFG?" commond to get DNS servers address */
+        if (at_obj_exec_cmd(device->client, resp, "AT+CDNSCFG?") < 0)
+        {
+            result = -RT_ERROR;
+            goto __exit;
+        }
+
+        if (at_resp_parse_line_args_by_kw(resp, "PrimaryDns:", "PrimaryDns:%s", dns_server1) <= 0 ||
+            at_resp_parse_line_args_by_kw(resp, "SecondaryDns:", "SecondaryDns:%s", dns_server2) <= 0)
+        {
+            LOG_E("Prase \"AT+CDNSCFG?\" commands resposne data error!");
+            result = -RT_ERROR;
+            goto __exit;
+        }
+
+        LOG_D("a9g device(%s) primary DNS server address: %s", device->name, dns_server1);
+        LOG_D("a9g device(%s) secondary DNS server address: %s", device->name, dns_server2);
+
+        inet_aton(dns_server1, &addr);
+        netdev_low_level_set_dns_server(netdev, 0, &addr);
+
+        inet_aton(dns_server2, &addr);
+        netdev_low_level_set_dns_server(netdev, 1, &addr);
+    }
+
+__exit:
+    if (resp)
+    {
+        at_delete_resp(resp);
+    }
+    
+    return result;
+}
+
+static void check_link_status_entry(void *parameter)
+{
+#define A9G_LINK_STATUS_OK   1
+#define A9G_LINK_RESP_SIZE   128
+#define A9G_LINK_RESP_TIMO   (3 * RT_TICK_PER_SECOND)
+#define A9G_LINK_DELAY_TIME  (30 * RT_TICK_PER_SECOND)
+
+    at_response_t resp = RT_NULL;
+    int result_code, link_status;
+    struct at_device *device = RT_NULL;
+    struct netdev *netdev = (struct netdev *)parameter;
+
+    device = at_device_get_by_name(AT_DEVICE_NAMETYPE_NETDEV, netdev->name);
+    if (device == RT_NULL)
+    {
+        LOG_E("get device(%s) failed.", netdev->name);
+        return;
+    }
+
+    resp = at_create_resp(A9G_LINK_RESP_SIZE, 0, A9G_LINK_RESP_TIMO);
+    if (resp == RT_NULL)
+    {
+        LOG_E("no memory for response create.");
+        return;
+    }
+
+    while (1)
+    {
+        /* send "AT+CREG?" commond  to check netweork interface device link status */
+        if (at_obj_exec_cmd(device->client, resp, "AT+CREG?") < 0)
+        {
+            rt_thread_mdelay(A9G_LINK_DELAY_TIME);
+            continue;
+        }
+        link_status = -1;
+        at_resp_parse_line_args_by_kw(resp, "+CREG:", "+CREG: %d,%d", &result_code, &link_status);
+
+        /* check the network interface device link status  */
+        if ((A9G_LINK_STATUS_OK == link_status) != netdev_is_link_up(netdev))
+        {
+            netdev_low_level_set_link_status(netdev, (A9G_LINK_STATUS_OK == link_status));
+        }
+        rt_thread_mdelay(A9G_LINK_DELAY_TIME);
+    }
+}
+
+static int a9g_netdev_check_link_status(struct netdev *netdev)
+{
+#define a9g_LINK_THREAD_TICK           20
+#define a9g_LINK_THREAD_STACK_SIZE     512
+#define a9g_LINK_THREAD_PRIORITY       (RT_THREAD_PRIORITY_MAX - 2)
+
+    rt_thread_t tid;
+    char tname[RT_NAME_MAX] = {0};
+
+    if (netdev == RT_NULL)
+    {
+        LOG_E("input network interface device is NULL.\n");
+        return -RT_ERROR;
+    }
+
+    rt_snprintf(tname, RT_NAME_MAX, "%s_link", netdev->name);
+
+    tid = rt_thread_create(tname, check_link_status_entry, (void *) netdev, 
+            a9g_LINK_THREAD_STACK_SIZE, a9g_LINK_THREAD_PRIORITY, a9g_LINK_THREAD_TICK);
+    if (tid)
+    {
+        rt_thread_startup(tid);
+    }
+
+    return RT_EOK;
+}
+
+static int a9g_net_init(struct at_device *device);
+
+static int a9g_netdev_set_up(struct netdev *netdev)
+{
+    struct at_device *device = RT_NULL;
+
+    device = at_device_get_by_name(AT_DEVICE_NAMETYPE_NETDEV, netdev->name);
+    if (device == RT_NULL)
+    {
+        LOG_E("get a9g device by netdev name(%s) failed.", netdev->name);
+        return -RT_ERROR;
+    }
+
+    if (device->is_init == RT_FALSE)
+    {
+        a9g_net_init(device);
+        device->is_init = RT_TRUE;
+        
+        netdev_low_level_set_status(netdev, RT_TRUE);
+        LOG_D("the network interface device(%s) set up status.", netdev->name);
+    }
+
+    return RT_EOK;
+}
+
+static int a9g_netdev_set_down(struct netdev *netdev)
+{
+    struct at_device *device = RT_NULL;
+
+    device = at_device_get_by_name(AT_DEVICE_NAMETYPE_NETDEV, netdev->name);
+    if (device == RT_NULL)
+    {
+        LOG_E("get a9g device by netdev name(%s) failed.", netdev->name);
+        return -RT_ERROR;
+    }
+
+    if (device->is_init == RT_TRUE)
+    {
+        a9g_power_off(device);
+        device->is_init = RT_FALSE;
+
+        netdev_low_level_set_status(netdev, RT_FALSE);
+        LOG_D("the network interface device(%s) set down status.", netdev->name);
+    }
+
+    return RT_EOK;
+}
+
+static int a9g_netdev_set_dns_server(struct netdev *netdev, uint8_t dns_num, ip_addr_t *dns_server)
+{
+#define a9g_DNS_RESP_LEN     8
+#define a9g_DNS_RESP_TIMEO   rt_tick_from_millisecond(300)
+
+    int result = RT_EOK;
+    at_response_t resp = RT_NULL;
+    struct at_device *device = RT_NULL;
+
+    RT_ASSERT(netdev);
+    RT_ASSERT(dns_server);
+
+    device = at_device_get_by_name(AT_DEVICE_NAMETYPE_NETDEV, netdev->name);
+    if (device == RT_NULL)
+    {
+        LOG_E("get a9g device by netdev name(%s) failed.", netdev->name);
+        return -RT_ERROR;
+    }
+
+    resp = at_create_resp(a9g_DNS_RESP_LEN, 0, a9g_DNS_RESP_TIMEO);
+    if (resp == RT_NULL)
+    {
+        LOG_D("a9g set dns server failed, no memory for response object.");
+        result = -RT_ENOMEM;
+        goto __exit;
+    }
+
+    /* send "AT+CDNSCFG=<pri_dns>[,<sec_dns>]" commond to set dns servers */
+    if (at_obj_exec_cmd(device->client, resp, "AT+CDNSCFG=\"%s\"", inet_ntoa(*dns_server)) < 0)
+    {
+        result = -RT_ERROR;
+        goto __exit;
+    }
+
+    netdev_low_level_set_dns_server(netdev, dns_num, dns_server);
+
+__exit:
+    if (resp)
+    {
+        at_delete_resp(resp);
+    }
+
+    return result;
+}
+
+static int a9g_ping_domain_resolve(struct at_device *device, const char *name, char ip[16])
+{
+    int result = RT_EOK;
+    char recv_ip[16] = { 0 };
+    at_response_t resp = RT_NULL;
+
+    /* The maximum response time is 14 seconds, affected by network status */
+    resp = at_create_resp(512, 4, 14 * RT_TICK_PER_SECOND);
+    if (resp == RT_NULL)
+    {
+        LOG_E("no memory for a9g device(%s) response structure.", device->name);
+        return -RT_ENOMEM;
+    }
+
+    if (at_obj_exec_cmd(device->client, resp, "AT+CGACT=1,1") < 0)
+    {
+        result = -RT_ERROR;
+        goto __exit;
+    }
+
+    if (at_obj_exec_cmd(device->client, resp, "AT+CDNSGIP=\"%s\"", name) < 0)
+    {
+        result = -RT_ERROR;
+        goto __exit;
+    }
+	
+    if (at_resp_parse_line_args_by_kw(resp, "+CDNSGIP:", "%*[^,],%*[^,],\"%[^\"]", recv_ip) < 0)
+    {
+        rt_thread_mdelay(100);
+        /* resolve failed, maybe receive an URC CRLF */
+    }
+
+    if (rt_strlen(recv_ip) < 8)
+    {
+        rt_thread_mdelay(100);
+        /* resolve failed, maybe receive an URC CRLF */
+    }
+    else
+    {
+        rt_strncpy(ip, recv_ip, 15);
+        ip[15] = '\0';
+    }
+
+__exit:
+    if (resp)
+    {
+        at_delete_resp(resp);
+    }
+
+    return result;
+}
+
+#ifdef NETDEV_USING_PING
+#ifdef AT_DEVICE_USING_A9G
+static int a9g_netdev_ping(struct netdev *netdev, const char *host, 
+        size_t data_len, uint32_t timeout, struct netdev_ping_resp *ping_resp)
+{
+    rt_kprintf("I don't have PING function!\r\n");
+    return RT_EOK;
+}
+#endif
+#endif /* NETDEV_USING_PING */
+
+#ifdef NETDEV_USING_NETSTAT
+void a9g_netdev_netstat(struct netdev *netdev)
+{ 
+    // TODO netstat support
+}
+#endif /* NETDEV_USING_NETSTAT */
+
+const struct netdev_ops a9g_netdev_ops =
+{
+    a9g_netdev_set_up,
+    a9g_netdev_set_down,
+
+    RT_NULL, /* not support set ip, netmask, gatway address */
+    a9g_netdev_set_dns_server,
+    RT_NULL, /* not support set DHCP status */
+
+#ifdef NETDEV_USING_PING
+    a9g_netdev_ping,
+#endif
+#ifdef NETDEV_USING_NETSTAT
+    a9g_netdev_netstat,
+#endif
+};
+
+static struct netdev *a9g_netdev_add(const char *netdev_name)
+{
+#define A9G_NETDEV_MTU       1500
+    struct netdev *netdev = RT_NULL;
+
+    RT_ASSERT(netdev_name);
+
+    netdev = (struct netdev *) rt_calloc(1, sizeof(struct netdev));
+    if (netdev == RT_NULL)
+    {
+        LOG_E("no memory for a9g device(%s) netdev structure.", netdev_name);
+        return RT_NULL;
+    }
+
+    netdev->mtu = A9G_NETDEV_MTU;
+    netdev->ops = &a9g_netdev_ops;
+
+#ifdef SAL_USING_AT
+    extern int sal_at_netdev_set_pf_info(struct netdev *netdev);
+    /* set the network interface socket/netdb operations */
+    sal_at_netdev_set_pf_info(netdev);
+#endif
+
+    netdev_register(netdev, netdev_name, RT_NULL);
+
+    return netdev;
+}
+
+/* =============================  a9g device operations ============================= */
+
+#define AT_SEND_CMD(client, resp, resp_line, timeout, cmd)                                         \
+    do {                                                                                           \
+        (resp) = at_resp_set_info((resp), 128, (resp_line), rt_tick_from_millisecond(timeout));    \
+        if (at_obj_exec_cmd((client), (resp), (cmd)) < 0)                                          \
+        {                                                                                          \
+            result = -RT_ERROR;                                                                    \
+            goto __exit;                                                                           \
+        }                                                                                          \
+    } while(0)                                                                                     \
+
+/* init for a9g */
+static void a9g_init_thread_entry(void *parameter)
+{
+#define INIT_RETRY                     5
+#define CPIN_RETRY                     10
+#define CSQ_RETRY                      10
+#define CREG_RETRY                     10
+#define CGREG_RETRY                    20
+
+    int i, qimux, retry_num = INIT_RETRY;
+    char parsed_data[10] = {0};
+    rt_err_t result = RT_EOK;
+    at_response_t resp = RT_NULL;
+    struct at_device *device = (struct at_device *)parameter;
+    struct at_client *client = device->client;
+
+    resp = at_create_resp(128, 0, rt_tick_from_millisecond(300));
+    if (resp == RT_NULL)
+    {
+        LOG_E("no memory for a9g device(%s) response structure.", device->name);
+        return;
+    }
+
+    LOG_D("start initializing the device(%s)", device->name);
+
+    while (retry_num--)
+    {
+        rt_memset(parsed_data, 0, sizeof(parsed_data));
+        rt_thread_mdelay(500);
+        a9g_power_on(device);
+        rt_thread_mdelay(1000);
+
+        /* wait a9g startup finish */
+        if (at_client_obj_wait_connect(client, A9G_WAIT_CONNECT_TIME))
+        {
+            result = -RT_ETIMEOUT;
+            goto __exit;
+        }
+
+        /* disable echo */
+        AT_SEND_CMD(client, resp, 0, 300, "ATE0");
+        /* get module version */
+        AT_SEND_CMD(client, resp, 5, 300, "ATI");
+        /* show module version */
+        for (i = 0; i < (int)resp->line_counts - 1; i++)
+        {
+            LOG_D("%s", at_resp_get_line(resp, i + 1));
+        }
+        /* check SIM card */
+        for (i = 0; i < CPIN_RETRY; i++)
+        {
+            AT_SEND_CMD(client, resp, 2, 10 * 1000, "AT+CCID");
+            if (at_resp_get_line_by_kw(resp, "+CCID:"))
+            {
+                LOG_D("a9g device(%s) SIM card detection success.", device->name);
+                break;
+            }
+            rt_thread_mdelay(1000);
+        }
+        if (i == CPIN_RETRY)
+        {
+            LOG_E("a9g device(%s) SIM card detection failed.", device->name);
+            result = -RT_ERROR;
+            goto __exit;
+        }
+		
+		/* make the device restart */
+        AT_SEND_CMD(client, resp, 0, 300, "AT+RST=1");
+        for(i = 0; i<=30; i++)
+        {
+            i++;
+            rt_thread_mdelay(1000);
+        }
+		
+        /* waiting for dirty data to be digested */
+        rt_thread_mdelay(1000);
+
+        /* check the GSM network is registered */
+        for (i = 0; i < CREG_RETRY; i++)
+        {
+            AT_SEND_CMD(client, resp, 0, 300, "AT+CREG?");
+            at_resp_parse_line_args_by_kw(resp, "+CREG:", "+CREG: %s", &parsed_data);
+            if (!strncmp(parsed_data, "1,1", sizeof(parsed_data)) ||
+                !strncmp(parsed_data, "1,5", sizeof(parsed_data)))
+            {
+                LOG_D("a9g device(%s) GSM network is registered(%s),", device->name, parsed_data);
+                break;
+            }
+            rt_thread_mdelay(1000 + 500 * (i+1));
+        }
+        if (i == CREG_RETRY)
+        {
+            LOG_E("a9g device(%s) GSM network is register failed(%s).", device->name, parsed_data);
+            result = -RT_ERROR;
+            goto __exit;
+        }
+
+        /* the device default response timeout is 40 seconds, but it set to 15 seconds is convenient to use. */
+        for (uint8_t ii = 0; ii < INIT_RETRY; ii++)
+        {
+            resp = at_resp_set_info(resp, 128, 0, rt_tick_from_millisecond(10 * 1000));
+            if (at_obj_exec_cmd(client, resp, "AT+CGATT=0") == RT_EOK)
+            {
+                break;
+            }
+            rt_thread_mdelay(1000);
+        }
+        
+        /* check the GPRS network is registered */
+        for (i = 0; i < CGREG_RETRY; i++)
+        {
+            for (uint8_t ii = 0; ii < INIT_RETRY; ii++)
+            {
+                //AT_SEND_CMD(client, resp, 0, 5 * 1000, "AT+CGATT=1");
+                resp = at_resp_set_info(resp, 128, 0, rt_tick_from_millisecond(10 * 1000));
+                if (at_obj_exec_cmd(client, resp, "AT+CGATT=1") == RT_EOK)
+                {
+                    break;
+                }
+                rt_thread_mdelay(1000);
+            }
+			
+            AT_SEND_CMD(client, resp, 0, 1000, "AT+CGDCONT=1,\"IP\",\"CMNET\"");
+            rt_thread_mdelay(10);
+            AT_SEND_CMD(client, resp, 0, 5 * 1000, "AT+CGACT=1,1");
+            rt_thread_mdelay(10);
+            at_resp_parse_line_args_by_kw(resp, "OK", "%s", &parsed_data);
+            
+			if (!strncmp(parsed_data, "OK", sizeof(parsed_data)))
+            {
+                LOG_D("a9g device(%s) GPRS network is registered(%s).", device->name, parsed_data);
+                break;
+            }
+            rt_thread_mdelay(1000);
+        }
+        if (i == CGREG_RETRY)
+        {
+            LOG_E("a9g device(%s) GPRS network is register failed(%s).", device->name, parsed_data);
+            result = -RT_ERROR;
+            goto __exit;
+        }
+
+        /* check signal strength */
+        for (i = 0; i < CSQ_RETRY; i++)
+        {
+            AT_SEND_CMD(client, resp, 0, 300, "AT+CSQ");
+            at_resp_parse_line_args_by_kw(resp, "+CSQ:", "+CSQ: %s", &parsed_data);
+            if (strncmp(parsed_data, "99,99", sizeof(parsed_data)))
+            {
+                LOG_D("a9g device(%s) signal strength: %s", device->name, parsed_data);
+                break;
+            }
+            rt_thread_mdelay(1000);
+        }
+        if (i == CSQ_RETRY)
+        {
+            LOG_E("a9g device(%s) signal strength check failed (%s)", device->name, parsed_data);
+            result = -RT_ERROR;
+            goto __exit;
+        }
+
+        /* Set to multiple connections */
+        AT_SEND_CMD(client, resp, 0, 300, "AT+CIPMUX?");
+
+        at_resp_parse_line_args_by_kw(resp, "+CIPMUX:", "+CIPMUX:%d", &qimux);
+
+        if (qimux == 0)
+        {
+            AT_SEND_CMD(client, resp, 0, 1 * 1000, "AT+CIPMUX=1");
+        }
+
+        AT_SEND_CMD(client, resp, 0, 300, "AT+COPS?");
+        at_resp_parse_line_args_by_kw(resp, "+COPS:", "+COPS: %*[^\"]\"%[^\"]", &parsed_data);
+        if (rt_strcmp(parsed_data, "CHINA MOBILE") == 0)
+        {
+            /* "CMCC" */
+            LOG_I("a9g device(%s) network operator: %s", device->name, parsed_data);
+            AT_SEND_CMD(client, resp, 0, 300, CSTT_CHINA_MOBILE);
+        }
+        else if (rt_strcmp(parsed_data, "CHN-UNICOM") == 0)
+        {
+            /* "UNICOM" */
+            LOG_I("a9g device(%s) network operator: %s", device->name, parsed_data);
+            AT_SEND_CMD(client, resp, 0, 300, CSTT_CHINA_UNICOM);
+        }
+        else if (rt_strcmp(parsed_data, "CHN-CT") == 0)
+        {
+            AT_SEND_CMD(client, resp, 0, 300, CSTT_CHINA_TELECOM);
+            /* "CT" */
+            LOG_I("a9g device(%s) network operator: %s", device->name, parsed_data);
+        }
+
+        AT_SEND_CMD(client, resp, 2, 300, "AT+CIFSR");
+        if (at_resp_get_line_by_kw(resp, "ERROR") != RT_NULL)
+        {
+            LOG_E("a9g device(%s) get the local address failed.", device->name);
+            result = -RT_ERROR;
+            goto __exit;
+        }
+#ifdef	AT_USING_A9G_GPS
+        AT_SEND_CMD(client, resp, 0, 300, "AT+GPS?");
+        at_resp_parse_line_args_by_kw(resp, "+GPS:", "+GPS: %d", &qimux);
+        if (qimux == 0)
+        {
+            AT_SEND_CMD(client, resp, 0, 300, "AT+GPS=1");
+        }
+#endif
+        result = RT_EOK;
+
+__exit:
+        if (result == RT_EOK)
+        {
+            break;
+        }
+        else
+        {
+            /* power off the a9g device */
+            a9g_power_off(device);
+            rt_thread_mdelay(1000);
+
+            LOG_I("a9g device(%s) initialize retry...", device->name);
+        }
+    }
+
+    if (resp)
+    {
+        at_delete_resp(resp);
+    }
+
+    if (result == RT_EOK)
+    {
+        device->is_init = RT_TRUE;
+        
+        /* set network interface device status and address information */
+        a9g_netdev_set_info(device->netdev);
+        /*  */
+        a9g_netdev_check_link_status(device->netdev);
+        /*  */
+        LOG_I("a9g device(%s) network initialize success!", device->name);
+
+    }
+    else
+    {
+        device->is_init = RT_FALSE;
+        
+        netdev_low_level_set_status(device->netdev, RT_FALSE);
+        LOG_E("a9g device(%s) network initialize failed(%d)!", device->name, result);
+    }
+}
+
+static int a9g_net_init(struct at_device *device)
+{
+#ifdef AT_DEVICE_A9G_INIT_ASYN
+    rt_thread_t tid;
+
+    tid = rt_thread_create("a9g_net_init", a9g_init_thread_entry, (void *)device,
+                A9G_THREAD_STACK_SIZE, A9G_THREAD_PRIORITY, 20);
+    if (tid)
+    {
+        rt_thread_startup(tid);
+    }
+    else
+    {
+        LOG_E("create a9g device(%s) initialization thread failed.", device->name);
+        return -RT_ERROR;
+    }
+#else
+    a9g_init_thread_entry(device);
+#endif /* AT_DEVICE_a9g_INIT_ASYN */
+
+    return RT_EOK;
+}
+
+static void urc_func(struct at_client *client, const char *data, rt_size_t size)
+{
+    RT_ASSERT(data);
+
+    LOG_I("URC data : %.*s", size, data);
+}
+
+/* a9g device URC table for the device control */
+static const struct at_urc urc_table[] = 
+{
+        {"READY",         "\r\n",                 urc_func},
+};
+
+static int a9g_init(struct at_device *device)
+{
+    struct at_device_a9g *a9g = (struct at_device_a9g *) device->user_data;
+
+    /* initialize AT client */
+    at_client_init(a9g->client_name, a9g->recv_line_num);
+
+    device->client = at_client_get(a9g->client_name);
+    if (device->client == RT_NULL)
+    {
+        LOG_E("a9g device(%s) initialize failed, get AT client(%s) failed.", a9g->device_name, a9g->client_name);
+        return -RT_ERROR;
+    }
+
+    /* register URC data execution function  */
+    at_obj_set_urc_table(device->client, urc_table, sizeof(urc_table) / sizeof(urc_table[0]));
+
+#ifdef AT_USING_SOCKET
+    a9g_socket_init(device);
+#endif
+
+    /* add a9g device to the netdev list */
+    device->netdev = a9g_netdev_add(a9g->device_name);
+    if (device->netdev == RT_NULL)
+    {
+        LOG_E("a9g device(%s) initialize failed, get network interface device failed.", a9g->device_name);
+        return -RT_ERROR;
+    }
+	
+	/* initialize a9g pin configuration */
+    if (a9g->power_pin != -1 && a9g->power_status_pin != -1)
+    {
+        rt_pin_mode(a9g->power_pin, PIN_MODE_OUTPUT);
+        rt_pin_mode(a9g->power_status_pin, PIN_MODE_INPUT);
+    }
+
+    /* initialize a9g device network */
+    return a9g_netdev_set_up(device->netdev);
+}
+
+static int a9g_deinit(struct at_device *device)
+{
+    return a9g_netdev_set_down(device->netdev);
+}
+
+static int a9g_control(struct at_device *device, int cmd, void *arg)
+{
+    int result = -RT_ERROR;
+
+    RT_ASSERT(device);
+
+    switch (cmd)
+    {
+    case AT_DEVICE_CTRL_POWER_ON:
+    case AT_DEVICE_CTRL_POWER_OFF:
+    case AT_DEVICE_CTRL_RESET:
+    case AT_DEVICE_CTRL_LOW_POWER:
+    case AT_DEVICE_CTRL_SLEEP:
+    case AT_DEVICE_CTRL_WAKEUP:
+    case AT_DEVICE_CTRL_NET_CONN:
+    case AT_DEVICE_CTRL_NET_DISCONN:
+    case AT_DEVICE_CTRL_SET_WIFI_INFO:
+    case AT_DEVICE_CTRL_GET_SIGNAL:
+    case AT_DEVICE_CTRL_GET_GPS:
+    case AT_DEVICE_CTRL_GET_VER:
+        LOG_W("a9g not support the control command(%d).", cmd);
+        break;
+    default:
+        LOG_E("input error control command(%d).", cmd);
+        break;
+    }
+
+    return result;
+}
+
+const struct at_device_ops a9g_device_ops = 
+{
+    a9g_init,
+    a9g_deinit,
+    a9g_control,
+};
+
+static int a9g_device_class_register(void)
+{
+    struct at_device_class *class = RT_NULL;
+
+    class = (struct at_device_class *) rt_calloc(1, sizeof(struct at_device_class));
+    if (class == RT_NULL)
+    {
+        LOG_E("no memory for a9g device class create.");
+        return -RT_ENOMEM;
+    }
+
+    /* fill a9g device class object */
+#ifdef AT_USING_SOCKET
+    a9g_socket_class_register(class);
+#endif
+    class->device_ops = &a9g_device_ops;
+
+    return at_device_class_register(class, AT_DEVICE_CLASS_A9G);
+}
+INIT_DEVICE_EXPORT(a9g_device_class_register);
+
+#endif /* AT_DEVICE_USING_a9g */
diff --git a/class/a9g/at_device_a9g.h b/class/a9g/at_device_a9g.h
new file mode 100644
index 0000000..38be45a
--- /dev/null
+++ b/class/a9g/at_device_a9g.h
@@ -0,0 +1,67 @@
+/*
+ * File      : at_device_a9g.h
+ * This file is part of RT-Thread RTOS
+ * COPYRIGHT (C) 2006 - 2018, RT-Thread Development Team
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2019-11-23     luliang    first version
+ */
+ 
+#ifndef __A9G_DEVICE_H__
+#define __A9G_DEVICE_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdlib.h>
+
+#include <at_device.h>
+
+/* The maximum number of sockets supported by the a9g device */
+#define AT_DEVICE_A9G_SOCKETS_NUM		8
+
+struct at_device_a9g
+{
+	char *device_name;
+	char *client_name;
+	
+	int power_pin;
+	int power_status_pin;
+	size_t recv_line_num;
+	struct at_device device;
+	
+	void *user_data;
+};
+
+#ifdef AT_USING_SOCKET
+
+/* a9g device socket initialize */
+int a9g_socket_init(struct at_device *device);
+
+/* a9g device class socket register */
+int a9g_socket_class_register(struct at_device_class *class);
+
+#endif /* AT_USING_SOCKET */
+
+#ifdef __cplusplus
+}
+#endif
+
+
+#endif	/*	__AT_DEVICE_A9G_H__*/
diff --git a/class/a9g/at_socket_a9g.c b/class/a9g/at_socket_a9g.c
new file mode 100644
index 0000000..aeb1ca0
--- /dev/null
+++ b/class/a9g/at_socket_a9g.c
@@ -0,0 +1,623 @@
+/*
+ * File      : at_socket_a9g.c
+ * This file is part of RT-Thread RTOS
+ * COPYRIGHT (C) 2006 - 2018, RT-Thread Development Team
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2019-11-23     luliang    first version
+ */
+ 
+#include <stdio.h>
+#include <string.h>
+
+#include <at_device_a9g.h>
+
+#define LOG_TAG                        "at.skt.a9g"
+#include <at_log.h>
+
+#if defined(AT_DEVICE_USING_A9G) && defined(AT_USING_SOCKET)
+
+#define A9G_MODULE_SEND_MAX_SIZE   1000
+
+/* set real event by current socket and current state */
+#define SET_EVENT(socket, event)       (((socket + 1) << 16) | (event))
+
+/* AT socket event type */
+#define A9G_EVENT_CONN_OK          (1L << 0)
+#define A9G_EVENT_SEND_OK          (1L << 1)
+#define A9G_EVENT_RECV_OK          (1L << 2)
+#define A9G_EVENT_CLOSE_OK         (1L << 3)
+#define A9G_EVENT_CONN_FAIL        (1L << 4)
+#define A9G_EVENT_SEND_FAIL        (1L << 5)
+
+static at_evt_cb_t at_evt_cb_set[] = {
+        [AT_SOCKET_EVT_RECV] = NULL,
+        [AT_SOCKET_EVT_CLOSED] = NULL,
+};
+
+static int a9g_socket_event_send(struct at_device *device, uint32_t event)
+{
+    return (int) rt_event_send(device->socket_event, event);
+}
+
+static int a9g_socket_event_recv(struct at_device *device, uint32_t event, uint32_t timeout, rt_uint8_t option)
+{
+    int result = RT_EOK;
+    rt_uint32_t recved;
+
+    result = rt_event_recv(device->socket_event, event, option | RT_EVENT_FLAG_CLEAR, timeout, &recved);
+    if (result != RT_EOK)
+    {
+        return -RT_ETIMEOUT;
+    }
+
+    return recved;
+}
+
+/**
+ * close socket by AT commands.
+ *
+ * @param current socket
+ *
+ * @return  0: close socket success
+ *         -1: send AT commands error
+ *         -2: wait socket event timeout
+ *         -5: no memory
+ */
+static int a9g_socket_close(struct at_socket *socket)
+{
+    int result = RT_EOK;
+    at_response_t resp = RT_NULL;
+    int device_socket = (int) socket->user_data;
+    struct at_device *device = (struct at_device *) socket->device;
+    
+    resp = at_create_resp(64, 0, rt_tick_from_millisecond(600));
+    
+    if (resp == RT_NULL)
+    {
+        LOG_E("no memory for a9g device(%s) response creat.", device->name);
+        return -RT_ENOMEM;
+    }
+    
+    if (at_obj_exec_cmd(device->client, resp, "AT+CIPCLOSE=%d", device_socket) < 0)
+    {
+        result = -RT_ERROR;
+        goto __exit;
+    }
+
+__exit:
+    if (resp)
+    {
+        at_delete_resp(resp);
+    }
+    
+    return result;
+}
+
+
+/**
+ * create TCP/UDP client or server connect by AT commands.
+ *
+ * @param socket current socket
+ * @param ip server or client IP address
+ * @param port server or client port
+ * @param type connect socket type(tcp, udp)
+ * @param is_client connection is client
+ *
+ * @return   0: connect success
+ *          -1: connect failed, send commands error or type error
+ *          -2: wait socket event timeout
+ *          -5: no memory
+ */
+static int a9g_socket_connect(struct at_socket *socket, char *ip, int32_t port, enum at_socket_type type, rt_bool_t is_client)
+{
+    uint32_t event = 0;
+    rt_bool_t retryed = RT_FALSE;
+    at_response_t resp = RT_NULL;
+    int result = RT_EOK, event_result = 0;
+    int device_socket = (int) socket->user_data;
+    struct at_device *device = (struct at_device *) socket->device;
+
+    RT_ASSERT(ip);
+    RT_ASSERT(port >= 0);
+
+    resp = at_create_resp(128, 0, 5 * RT_TICK_PER_SECOND);
+    if (resp == RT_NULL)
+    {
+        LOG_E("no memory for a9g device(%s) response structure.", device->name);
+        return -RT_ENOMEM;
+    }
+
+__retry:
+
+    /* clear socket connect event */
+    event = SET_EVENT(device_socket, A9G_EVENT_CONN_OK | A9G_EVENT_CONN_FAIL);
+    a9g_socket_event_recv(device, event, 0, RT_EVENT_FLAG_OR);
+
+    if (is_client)
+    {
+        switch (type)
+        {
+        case AT_SOCKET_TCP:
+            /* send AT commands(eg: AT+QIOPEN=0,"TCP","x.x.x.x", 1234) to connect TCP server */
+            if (at_obj_exec_cmd(device->client, RT_NULL, "AT+CIPSTART=\"TCP\",\"%s\",%d", ip, port) < 0)
+            {
+                result = -RT_ERROR;
+                goto __exit;
+            }
+            break;
+
+        case AT_SOCKET_UDP:
+            if (at_obj_exec_cmd(device->client, RT_NULL, "AT+CIPSTART=\"UDP\",\"%s\",%d", ip, port) < 0)
+            {
+                result = -RT_ERROR;
+                goto __exit;
+            }
+            break;
+
+        default:
+            LOG_E("a9g device(%s) not supported connect type : %d.", device->name, type);
+            result = -RT_ERROR;
+            goto __exit;
+        }
+			}
+
+    /* waiting result event from AT URC, the device default connection timeout is 75 seconds, but it set to 10 seconds is convenient to use */
+    if (a9g_socket_event_recv(device, SET_EVENT(device_socket, 0), 10 * RT_TICK_PER_SECOND, RT_EVENT_FLAG_OR) < 0)
+    {
+        LOG_E("a9g device(%s) socket(%d) connect failed, wait connect result timeout.",device->name, device_socket);
+        result = -RT_ETIMEOUT;
+        goto __exit;
+    }
+    /* waiting OK or failed result */
+    event_result = a9g_socket_event_recv(device, 
+            A9G_EVENT_CONN_OK | A9G_EVENT_CONN_FAIL, 1 * RT_TICK_PER_SECOND, RT_EVENT_FLAG_OR);
+    if (event_result < 0)
+    {
+        LOG_E("a9g device(%s) socket(%d) connect failed, wait connect OK|FAIL timeout.", device->name, device_socket);
+        result = -RT_ETIMEOUT;
+        goto __exit;
+    }
+    /* check result */
+    if (event_result & A9G_EVENT_CONN_FAIL)
+    {
+        if (retryed == RT_FALSE)
+        {
+            LOG_D("a9g device(%s) socket(%d) connect failed, maybe the socket was not be closed at the last time and now will retry.", 
+                    device->name, device_socket);
+            if (a9g_socket_close(socket) < 0)
+            {
+                result = -RT_ERROR;
+                goto __exit;
+            }
+            retryed = RT_TRUE;
+            goto __retry;
+        }
+        LOG_E("a9g device(%s) socket(%d) connect failed.", device->name, device_socket);
+        result = -RT_ERROR;
+        goto __exit;
+    }
+
+__exit:
+    if (resp)
+    {
+        at_delete_resp(resp);
+    }
+    
+    return result;
+}
+
+/**
+ * send data to server or client by AT commands.
+ *
+ * @param socket current socket
+ * @param buff send buffer
+ * @param bfsz send buffer size
+ * @param type connect socket type(tcp, udp)
+ *
+ * @return >=0: the size of send success
+ *          -1: send AT commands error or send data error
+ *          -2: waited socket event timeout
+ *          -5: no memory
+ */
+static int a9g_socket_send(struct at_socket *socket, const char *buff, size_t bfsz, enum at_socket_type type)
+{
+    int result = RT_EOK;
+    size_t cur_pkt_size = 0, sent_size = 0;
+    at_response_t resp = RT_NULL;
+    int device_socket = (int) socket->user_data;
+    struct at_device *device = (struct at_device *) socket->device;
+    rt_mutex_t lock = device->client->lock;
+
+    RT_ASSERT(buff);
+
+    resp = at_create_resp(128, 2, 5 * RT_TICK_PER_SECOND);
+    if (resp == RT_NULL)
+    {
+        LOG_E("no memory for a9g device(%s) response structure.", device->name);
+        return -RT_ENOMEM;
+    }
+
+    rt_mutex_take(lock, RT_WAITING_FOREVER);
+
+    /* set AT client end sign to deal with '>' sign.*/
+    at_obj_set_end_sign(device->client, '>');
+
+    while (sent_size < bfsz)
+    {
+        if (bfsz - sent_size < A9G_MODULE_SEND_MAX_SIZE)
+        {
+            cur_pkt_size = bfsz - sent_size;
+        }
+        else
+        {
+            cur_pkt_size = A9G_MODULE_SEND_MAX_SIZE;
+        }
+		
+        /* send the "AT+CIPSEND" commands to AT server than receive the '>' response on the first line. */
+        if (at_obj_exec_cmd(device->client, resp, "AT+CIPSEND=%d,%d", device_socket, cur_pkt_size) < 0)
+        {
+            result = -RT_ERROR;
+            goto __exit;
+        }
+		
+        /* send the real data to server or client */
+        result = (int) at_client_obj_send(device->client, buff + sent_size, cur_pkt_size);
+        if (result == 0)
+        {
+            result = -RT_ERROR;
+            goto __exit;
+        }
+		
+		/* waiting OK or failed result */
+        at_resp_set_info(resp, 128, 0, 30 * RT_TICK_PER_SECOND);
+        if (at_obj_exec_cmd(device->client, resp, "") < 0)
+        {
+            result = -RT_ERROR;
+            goto __exit;
+        }
+        at_resp_set_info(resp, 128, 2, 5 * RT_TICK_PER_SECOND);
+
+        sent_size += cur_pkt_size;
+    }
+
+__exit:
+    /* reset the end sign for data conflict */
+    at_obj_set_end_sign(device->client, 0);
+
+    rt_mutex_release(lock);
+
+    if (resp)
+    {
+        at_delete_resp(resp);
+    }
+
+    return result;
+}
+
+/**
+ * domain resolve by AT commands.
+ *
+ * @param name domain name
+ * @param ip parsed IP address, it's length must be 16
+ *
+ * @return  0: domain resolve success
+ *         -1: send AT commands error or response error
+ *         -2: wait socket event timeout
+ *         -5: no memory
+ */
+static int a9g_domain_resolve(const char *name, char ip[16])
+{
+#define RESOLVE_RETRY                  5
+
+    int i, result = RT_EOK;
+    char recv_ip[16] = { 0 };
+    at_response_t resp = RT_NULL;
+    struct at_device *device = RT_NULL;
+
+    RT_ASSERT(name);
+    RT_ASSERT(ip);
+
+    device = at_device_get_first_initialized();
+    if (device == RT_NULL)
+    {
+        LOG_E("get first initialization a9g device failed.");
+        return -RT_ERROR;
+    }
+
+    /* The maximum response time is 14 seconds, affected by network status */
+    resp = at_create_resp(1024, 3, 14 * RT_TICK_PER_SECOND);
+
+    if (resp == RT_NULL)
+    {
+        LOG_E("no memory for a9g device(%s) response structure.", device->name);
+        return -RT_ENOMEM;
+    }
+
+    for (i = 0; i < RESOLVE_RETRY; i++)
+    {
+        int err_code = 0;
+
+        if (at_obj_exec_cmd(device->client, resp, "AT+CDNSGIP=\"%s\"", name) < 0)
+        {
+            result = -RT_ERROR;
+            goto __exit;
+        }
+
+        /* domain name prase error options */
+        if (at_resp_parse_line_args_by_kw(resp, "+CDNSGIP:", "+CDNSGIP: 0,%d", &err_code) > 0)
+        {
+            /* 3 - network error, 8 - dns common error */
+            if (err_code == 3 || err_code == 8)
+            {
+                result = -RT_ERROR;
+                goto __exit;
+            }
+        }
+				
+        /* parse the third line of response data, get the IP address */
+				if (at_resp_parse_line_args_by_kw(resp, "+CDNSGIP:", "%*[^,],%*[^,],\"%[^\"]", recv_ip) < 0)
+        {
+            rt_thread_mdelay(100);
+            /* resolve failed, maybe receive an URC CRLF */
+            continue;
+        }
+
+        if (rt_strlen(recv_ip) < 8)
+        {
+            rt_thread_mdelay(100);
+            /* resolve failed, maybe receive an URC CRLF */
+            continue;
+        }
+        else
+        {
+            rt_thread_mdelay(10);
+            rt_strncpy(ip, recv_ip, 15);
+            ip[15] = '\0';
+            break;
+        }
+    }
+
+__exit:
+    if (resp)
+    {
+        at_delete_resp(resp);
+    }
+		
+    return result;
+}
+
+/**
+ * set AT socket event notice callback
+ *
+ * @param event notice event
+ * @param cb notice callback
+ */
+static void a9g_socket_set_event_cb(at_socket_evt_t event, at_evt_cb_t cb)
+{
+    if (event < sizeof(at_evt_cb_set) / sizeof(at_evt_cb_set[1]))
+    {
+        at_evt_cb_set[event] = cb;
+    }
+}
+
+static void urc_connect_func(struct at_client *client, const char *data, rt_size_t size)
+{
+    int device_socket = 0;
+    struct at_device *device = RT_NULL;
+    char *client_name = client->device->parent.name;
+
+    RT_ASSERT(data && size);
+
+    device = at_device_get_by_name(AT_DEVICE_NAMETYPE_CLIENT, client_name);
+    if (device == RT_NULL)
+    {
+        LOG_E("get a9g device by client name(%s) failed.", client_name);
+        return;
+    }
+
+    /* get the current socket by receive data */
+    sscanf(data, "%d,%*s", &device_socket);
+
+    if (strstr(data, "CONNECT OK"))
+    {
+        a9g_socket_event_send(device, SET_EVENT(device_socket, A9G_EVENT_CONN_OK));
+    }
+    else if (strstr(data, "CONNECT FAIL"))
+    {
+        a9g_socket_event_send(device, SET_EVENT(device_socket, A9G_EVENT_CONN_FAIL));
+    }
+}
+
+static void urc_send_func(struct at_client *client, const char *data, rt_size_t size)
+{
+    int device_socket = 0;
+    struct at_device *device = RT_NULL;
+    char *client_name = client->device->parent.name;
+
+    RT_ASSERT(data && size);
+
+    device = at_device_get_by_name(AT_DEVICE_NAMETYPE_CLIENT, client_name);
+    if (device == RT_NULL)
+    {
+        LOG_E("get a9g device by client name(%s) failed.", client_name);
+        return;
+    }
+
+    /* get the current socket by receive data */
+    sscanf(data, "%d,%*s", &device_socket);
+
+    if (rt_strstr(data, "SEND OK"))
+    {
+        a9g_socket_event_send(device, SET_EVENT(device_socket, A9G_EVENT_SEND_OK));
+    }
+    else if (rt_strstr(data, "SEND FAIL"))
+    {
+        a9g_socket_event_send(device, SET_EVENT(device_socket, A9G_EVENT_SEND_FAIL));
+    }
+}
+
+static void urc_close_func(struct at_client *client, const char *data, rt_size_t size)
+{
+    int device_socket = 0;
+    struct at_device *device = RT_NULL;
+    char *client_name = client->device->parent.name;
+
+    RT_ASSERT(data && size);
+
+    device = at_device_get_by_name(AT_DEVICE_NAMETYPE_CLIENT, client_name);
+    if (device == RT_NULL)
+    {
+        LOG_E("get a9g device by client name(%s) failed.", client_name);
+        return;
+    }
+
+    /* get the current socket by receive data */
+    sscanf(data, "%d,%*s", &device_socket);
+
+    if (rt_strstr(data, "CLOSE OK"))
+    {
+        a9g_socket_event_send(device, SET_EVENT(device_socket, A9G_EVENT_CLOSE_OK));
+    }
+    else if (rt_strstr(data, "CLOSED"))
+    {
+        struct at_socket *socket = RT_NULL;
+
+        /* get AT socket object by device socket descriptor */
+        socket = &(device->sockets[device_socket]);
+
+        /* notice the socket is disconnect by remote */
+        if (at_evt_cb_set[AT_SOCKET_EVT_CLOSED])
+        {
+            at_evt_cb_set[AT_SOCKET_EVT_CLOSED](socket, AT_SOCKET_EVT_CLOSED, RT_NULL, 0);
+        }
+    }
+}
+
+static void urc_recv_func(struct at_client *client, const char *data, rt_size_t size)
+{
+    int device_socket = 0;
+    rt_int32_t timeout;
+    rt_size_t temp_size = 0;
+    char temp[8] = {0};
+    rt_size_t bfsz = 0;
+    char *recv_buf = RT_NULL;
+    struct at_socket *socket = RT_NULL;
+    struct at_device *device = RT_NULL;
+    char *client_name = client->device->parent.name;
+
+    RT_ASSERT(data && size);
+
+    /* get the current socket and receive buffer size by receive data */
+    sscanf(data, "+CIPRCV,%d,%d:", &device_socket, (int *) &bfsz);
+    /* get receive timeout by receive buffer length */
+    timeout = bfsz;
+
+    if (device_socket < 0 || bfsz == 0)
+    {
+        return;
+    }
+
+    device = at_device_get_by_name(AT_DEVICE_NAMETYPE_CLIENT, client_name);
+    if (device == RT_NULL)
+    {
+        LOG_E("get a9g device by client name(%s) failed.", client_name);
+        return;
+    }
+
+    recv_buf = (char *) rt_calloc(1, bfsz);
+    if (recv_buf == RT_NULL)
+    {
+        LOG_E("no memory for a9g device(%s) URC receive buffer (%d).", device->name, bfsz);
+        temp_size = (size-(rt_strstr(data,":")+1-data)-2);
+        /* read and clean the coming data */
+        while (temp_size < bfsz)
+        {
+            if (bfsz - temp_size > sizeof(temp))
+            {
+                at_client_obj_recv(client, temp, sizeof(temp), timeout);
+            }
+            else
+            {
+                at_client_obj_recv(client, temp, bfsz - temp_size, timeout);
+            }
+            temp_size += sizeof(temp);
+        }
+        return;
+    }
+
+    /* sync receive data */
+    temp_size = (size-(rt_strstr(data,":")+1-data)-2);
+    rt_memcpy(recv_buf,rt_strstr(data,":")+1,temp_size);
+    if (at_client_obj_recv(client, recv_buf+temp_size, bfsz-temp_size, timeout) != (bfsz-temp_size))
+    {
+        LOG_E("a9g device(%s) receive size(%d) data failed.", device->name, bfsz);
+        rt_free(recv_buf);
+        return;
+    }
+
+    /* get AT socket object by device socket descriptor */
+    socket = &(device->sockets[device_socket]);
+
+    /* notice the receive buffer and buffer size */
+    if (at_evt_cb_set[AT_SOCKET_EVT_RECV])
+    {
+        at_evt_cb_set[AT_SOCKET_EVT_RECV](socket, AT_SOCKET_EVT_RECV, recv_buf, bfsz);
+    }
+}
+
+/* A9G device URC table for the socket data */
+static const struct at_urc urc_table[] = 
+{
+    {"",            "CONNECT OK\r\n",      urc_connect_func},
+    {"",            ",CONNECT FAIL\r\n",   urc_connect_func},
+    {"",            ",SEND FAIL\r\n",      urc_send_func},
+    {"CLOSED:",     "\r\n",                urc_close_func},
+    {"+CIPRCV,",    "\r\n",                urc_recv_func},
+};
+
+static const struct at_socket_ops a9g_socket_ops = 
+{
+    a9g_socket_connect,
+    a9g_socket_close,
+    a9g_socket_send,
+    a9g_domain_resolve,
+    a9g_socket_set_event_cb,
+};
+
+int a9g_socket_init(struct at_device *device)
+{
+    RT_ASSERT(device);
+
+    /* register URC data execution function  */
+    at_obj_set_urc_table(device->client, urc_table, sizeof(urc_table) / sizeof(urc_table[0]));
+
+    return RT_EOK;
+}
+
+int a9g_socket_class_register(struct at_device_class *class)
+{
+    RT_ASSERT(class);
+
+    class->socket_num = AT_DEVICE_A9G_SOCKETS_NUM;
+    class->socket_ops = &a9g_socket_ops;
+
+    return RT_EOK;
+}
+
+#endif /* AT_DEVICE_USING_A9G && AT_USING_SOCKET */
diff --git a/samples/at_sample_a9g.c b/samples/at_sample_a9g.c
new file mode 100644
index 0000000..02a1984
--- /dev/null
+++ b/samples/at_sample_a9g.c
@@ -0,0 +1,52 @@
+/*
+ * File      : at_sample_a9g.c
+ * This file is part of RT-Thread RTOS
+ * COPYRIGHT (C) 2006 - 2018, RT-Thread Development Team
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2019-11-23     luliang     first version
+ */
+
+#include <at_device_a9g.h>
+
+#define LOG_TAG                   "at.sample.a9g"
+#include <at_log.h>
+
+#define A9G_SAMPLE_DEIVCE_NAME     "a9g0"
+
+static struct at_device_a9g a9g0 =
+{
+    A9G_SAMPLE_DEIVCE_NAME,
+    AT_DEVICE_NAME,
+		
+    A9G_SAMPLE_POWER_PIN,
+    A9G_SAMPLE_STATUS_PIN,
+    AT_DEVICE_RECV_BUFF_LEN,
+};
+
+static int a9g_device_register(void)
+{
+    struct at_device_a9g *a9g = &a9g0;
+
+    return at_device_register(&(a9g->device),
+                              a9g->device_name,
+                              a9g->client_name,
+                              AT_DEVICE_CLASS_A9G,
+                              (void *) a9g);
+}
+INIT_APP_EXPORT(a9g_device_register);