SIM900B GPRS模块 ————PPP拨号上网

1、编辑内核，使其支持PPP拨号上网

make menuconfig

Device Drivers ---> Network device support --->

  │ │    [*]     PPP multilink support (EXPERIMENTAL)                     │ │  
  │ │    [*]     PPP filtering                                            │ │  
  │ │    <*>     PPP support for async serial ports                       │ │  
  │ │    <*>     PPP support for sync tty ports                           │ │  
  │ │    <*>     PPP Deflate compression                                  │ │  
  │ │    <*>     PPP BSD-Compress compression                             │ │  
  │ │    <*>     PPP MPPE compression (encryption) (EXPERIMENTAL)         │ │  
  │ │    <*>     PPP over Ethernet (EXPERIMENTAL)                        │ │  

 │ │    <*>   PPP (point-to-point protocol) support                      │ │  

2、下载ppp-2.4.4.tar.gz

3、解压ppp-2.4.4.tar.gz文件

[huangan@localhost 3rdparty]$ tar -xzf ppp-2.4.4.tar.gz 

[huangan@localhost ppp-2.4.4]$ ls 
Changes-2.3  etc.ppp   modules   README          README.MSCHAP80  scripts
chat         FAQ       PLUGINS   README.cbcp     README.MSCHAP81  SETUP
common       include   pppd      README.eap-srp  README.pppoe     solaris
configure    linux     pppdump   README.linux    README.pwfd
contrib      Makefile  pppstats  README.MPPE     README.sol2

[huangan@localhost ppp-2.4.4]$ ./configure

。。。省略过程

[huangan@localhost ppp-2.4.4]$ make CC=/opt/buildroot-2012.08/arm920t/usr/bin/arm-linux-gcc 

。。。省略过程

编译结束后，会在chat 、pppd、pppdump、pppstats 四个目录下生成四个可执行文件，将他们移植到开发板上的\usr\sbin 路径下并给他们777的权限即可

4、制作脚本文件

vi /etc/ppp/peers/gprs


#set serialPort
/dev/ttyS1


#set buadrate
115200

#set flowdate
nocrtscts 

#to keep ppp on terminal
nodetach  

# Accept the peer's idea of our local IP address
ipcp-accept-local

# Accept the peer's idea of its (remote) IP address
ipcp-accept-remote

#dial up connetion as the default route
noauth
usepeerdns
noipdefault
defaultroute
user itlanger

connect '/usr/sbin/chat -s -v -f /etc/ppp/chat-gprs-connect'

vi  /etc/ppp/chat-gprs-connect


ABORT '\nBUSY\r'
ABORT '\nERROR\r'
ABORT '\nNO ANSWER\r'
ABORT '\nNO CARRIER\r'
ABORT '\nNO DIALTONE\r'


TIMEOUT 5
'' AT
OK ATE0
SAY "Press CTRL-C to break the connection process.\n"
OK 'AT+CGDCONT=1,"IP","CMNET"'
OK ATDT*99***1#       //这里要改成自己的运营商号码。。我的这个号码是移动的

SAY "Waiting for connect...\n"
CONNECT ''
SAY "Connect Success!\n"

5、开始测试

:>pppd call gprs&      (PS:& 是让这条命令在后台执行，这样我们才好去执行其他验证命令)

:>ping www.baidu.com

假如出现能ping通DNS 4.2.2.2  确ping不通百度 ，那就是DNS的问题

解决办法：vim /etc/resolv.conf

nameserver  4.2.2.2

nameserver 8.8.8.8

OK