[在线]高分请教一个EM310总返回error的错误，任何按键都返回Error，谢谢！

[erigido]

使用windows的拨号连接Gprs网络，并且作了一个检测的网络的服务，当发现网络不通时，重新拨号。手工测试都没有问题，晚上用计划任务每20分左右进行挂断，后发现如下现象：
正常的情况：
[2012-08-16 23:31:58:531] www.qq.com success
[2012-08-16 23:32:34:093] www.sina.com.cn success
[2012-08-16 23:32:34:640] www.baidu.com success
[2012-08-16 23:32:35:234] www.qq.com success
[2012-08-16 23:32:39:250] www.sina.com.cn success
[2012-08-16 23:32:39:796] www.baidu.com success
[2012-08-16 23:32:40:421] www.qq.com success
[2012-08-16 23:33:20:437] www.sina.com.cn failed
[2012-08-16 23:33:22:687] www.baidu.com failed
[2012-08-16 23:33:24:937] www.qq.com failed
[2012-08-16 23:33:30:187] www.sina.com.cn failed
[2012-08-16 23:33:32:437] www.baidu.com failed
[2012-08-16 23:33:34:687] www.qq.com failed
[2012-08-16 23:33:37:687] Gprs Modem RasHangUp
[2012-08-16 23:33:37:687] 监控端口串口号:COM1
[2012-08-16 23:33:38:312] ATE0 OK
[2012-08-16 23:33:38:937] 获取当前模块的状态 OK
[2012-08-16 23:33:39:562] 获取当前模块的型号 EM310
[2012-08-16 23:33:40:187] 获取当前SIM卡状态 +CPIN: READY
[2012-08-16 23:33:40:812] 当前网络的注册状态 +CREG: 0,1
[2012-08-16 23:33:41:437] 当前位置的信号质量 +CSQ: 29,99
[2012-08-16 23:33:42:062] 当前网络的类型 +COPS: 0,0,"CHINA MOBILE"

出错时
[2012-08-16 23:43:03:796] www.sina.com.cn failed
[2012-08-16 23:43:03:796] www.baidu.com failed
[2012-08-16 23:43:03:796] www.qq.com failed
[2012-08-16 23:43:06:796] www.sina.com.cn failed
[2012-08-16 23:43:06:796] www.baidu.com failed
[2012-08-16 23:43:06:796] www.qq.com failed
[2012-08-16 23:43:18:359] Gprs Modem RasHangUp
[2012-08-16 23:43:18:359] 监控端口串口号:COM1
[2012-08-16 23:43:18:984] ATE0 OK
[2012-08-16 23:43:19:609] 获取当前模块的状态 OK
[2012-08-16 23:43:20:234] 获取当前模块的型号 EM310
[2012-08-16 23:43:21:484] 当前网络的注册状态 +CREG: 0,0
[2012-08-16 23:43:22:109] 当前位置的信号质量 +CSQ: 29,99
[2012-08-16 23:43:22:734] 当前网络的类型 +COPS: 0
[2012-08-16 23:45:03:000] RasDialUp failed