使用树莓派连接EC20扩展版（如下图），进行ppp拨号，达到使用蜂窝网络上网的目的
树莓派版本：Raspberry 3B
操作系统版本：
4G模块：EC20
一、准备：
1、给拓展版插上SIM卡
2、将EC20拓展版插到Raspberry上
3、将EC20拓展版上的“数据/供电口”用USB线连到Raspberry的USB接口上，
4、查看是否能检测到
lsusb
5、检查
lsmod
6、进入/dev/目录查看ttyUSB设备，看是否识别模组设备。
ls /dev |grep ttyUSB
二、配置
1、 进入/etc/目录查看rc.local文件，添加如下设备信息【卖家教程里说要做这步，但是在自启动时会导致报错，注释掉也不影响上网】
echo ‘2c7c 0125 ff’ > /sys/bus/usb-serial/drivers/option1/new_id
echo ‘1c9e 9b05 ff’ > /sys/bus/usb-serial/drivers/option1/new_id
echo ‘2001 7e16 ff’ > /sys/bus/usb-serial/drivers/option1/new_id
echo ‘05c6 6000 ff’ > /sys/bus/usb-serial/drivers/option1/new_id
echo ‘05c6 9025 ff’ > /sys/bus/usb-serial/drivers/option1/new_id
echo ‘05c6 9020 ff’ > /sys/bus/usb-serial/drivers/option1/new_id
echo ‘05c6 9215 ff’ > /sys/bus/usb-serial/drivers/option1/new_id
echo ‘19d2 0579 ff’ > /sys/bus/usb-serial/drivers/option1/new_id
echo ‘2949 8247 ff’ > /sys/bus/usb-serial/drivers/option1/new_id
echo ‘1c9e 9b3c ff’ > /sys/bus/usb-serial/drivers/option1/new_id
2、新建配置文件（好像必须放在这个位置）：
sudo nano /etc/ppp/peer/myppp
文件内容如下
#/etc/ppp/peers/file_name
# Usage: root> pppd call file_name
# 调试时隐藏密码
hide-password
# 该手机不需要身份验证
noauth
#############################################
# 注意: 这里要知道chat安装的位置, 如果不在环境变量
# 里面, 则要指定位置(如 /usr/sbin/chat -s -v -f)
#############################################
# 用于呼叫控制脚本
connect 'chat -s -v -f /etc/ppp/peers/myppp-chat-connect'
# 断开连接脚本
disconnect 'chat -s -v -f /etc/ppp/peers/myppp-chat-disconnect'
# 调试信息
debug
# 模块串口设备
/dev/ttyUSB3
# 串口波特率
115200
# 使用默认路由
defaultroute
# 不能指定默认IP
noipdefault
# No ppp compression
novj
novjccomp
noccp
ipcp-accept-local
ipcp-accept-remote
local
# 最好锁定串行总线
lock
dump
nodetach
# Keep pppd attached to the terminal
# 用户名 密码
# user root
# password
# 硬件控制流
crtscts
remotename 3gppp
ipparam 3gppp
# 向对方请求最多2个DNS服务器地址
usepeerdns
3、新建连接文件：
sudo nano myppp-chat-connect
文件内容如下
TIMEOUT 15
# 连续15秒, 收到以下字符, 退出执行
ABORT "BUSY"
ABORT "NO CARRIER"
ABORT "NO DIALTONE"
ABORT "ERROR"
ABORT "NO ANSWER"
TIMEOUT 40
# 40秒内没有收到指定字符, 退出
# 如: OK \rATZ, 发送 ATZ, 希望收到的是 OK.
"" AT
OK \rATZ
# 建立连接: 移动的为cmnet\联通的为3gnet，根据自身情况修改
OK \rAT+CGDCONT=1,"IP","cmnet",,0,0
# 拨号
OK-AT-OK ATDT*99#
CONNECT \d\c
4、新建断开连接文件
sudo nano myppp-chat-disconnect
文件内容如下
ABORT "ERROR"
ABORT "NO DIALTONE"
SAY "\NSending break to the modem\n"
""\k"
""+++ATH"
SAY "\nGood bye !\n"
5、安装ppp
sudo apt-get install ppp
三、连网
1、连接【必须cd到 /etc/ppp/peer，否则报错】
pppd call myppp &
打印内容如下
pppd options in effect:
debug # (from /etc/ppp/peers/myppp)
nodetach # (from /etc/ppp/peers/myppp)
dump # (from /etc/ppp/peers/myppp)
noauth # (from /etc/ppp/peers/myppp)
remotename 3gppp # (from /etc/ppp/peers/myppp)
/dev/ttyUSB3 # (from /etc/ppp/peers/myppp)
115200 # (from /etc/ppp/peers/myppp)
lock # (from /etc/ppp/peers/myppp)
connect chat -s -v -f /etc/ppp/peers/myppp-chat-connect # (from /etc/ppp/peers/myppp)
disconnect chat -s -v -f /etc/ppp/peers/myppp-chat-disconnect # (from /etc/ppp/peers/myppp)
crtscts # (from /etc/ppp/peers/myppp)
local # (from /etc/ppp/peers/myppp)
asyncmap 0 # (from /etc/ppp/options)
lcp-echo-failure 4 # (from /etc/ppp/options)
lcp-echo-interval 30 # (from /etc/ppp/options)
hide-password # (from /etc/ppp/peers/myppp)
novj # (from /etc/ppp/peers/myppp)
novjccomp # (from /etc/ppp/peers/myppp)
ipcp-accept-local # (from /etc/ppp/peers/myppp)
ipcp-accept-remote # (from /etc/ppp/peers/myppp)
ipparam 3gppp # (from /etc/ppp/peers/myppp)
noipdefault # (from /etc/ppp/peers/myppp)
defaultroute # (from /etc/ppp/peers/myppp)
usepeerdns # (from /etc/ppp/peers/myppp)
noccp # (from /etc/ppp/peers/myppp)
noipx # (from /etc/ppp/options)
timeout set to 15 seconds
abort on (BUSY)
abort on (NO CARRIER)
abort on (NO DIALTONE)
abort on (ERROR)
abort on (NO ANSWER)
timeout set to 40 seconds
send (AT^M)
expect (OK)
AT^M^M
OK
-- got it
send (^MATZ^M)
expect (OK)
^M
ATZ^M^M
OK
-- got it
send (^MAT+CGDCONT=1,"IP","cmnet",,0,0^M)
expect (OK)
^M
AT+CGDCONT=1,"IP","cmnet",,0,0^M^M
OK
-- got it
send (ATDT*99#^M)
expect (CONNECT)
^M
ATDT*99#^M^M
CONNECT
-- got it
send (\d)
Script chat -s -v -f /etc/ppp/peers/myppp-chat-connect finished (pid 685), status = 0x0
Serial connection established.
using channel 1
Using interface ppp0
Connect: ppp0 <--> /dev/ttyUSB3
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x916190ae> <pcomp> <accomp>]
rcvd [LCP ConfReq id=0x0 <asyncmap 0x0> <auth chap MD5> <magic 0x79503a8c> <pcomp> <accomp>]
No auth is possible
sent [LCP ConfRej id=0x0 <auth chap MD5>]
rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x916190ae> <pcomp> <accomp>]
rcvd [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x79503a8c> <pcomp> <accomp>]
sent [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x79503a8c> <pcomp> <accomp>]
sent [LCP EchoReq id=0x0 magic=0x916190ae]
sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
rcvd [LCP DiscReq id=0x2 magic=0x79503a8c]
rcvd [LCP EchoRep id=0x0 magic=0x79503a8c 91 61 90 ae]
rcvd [IPCP ConfReq id=0x0]
sent [IPCP ConfNak id=0x0 <addr 0.0.0.0>]
rcvd [IPCP ConfNak id=0x1 <addr 10.115.59.42> <ms-dns1 211.136.20.203> <ms-dns2 211.136.17.107>]
sent [IPCP ConfReq id=0x2 <addr 10.115.59.42> <ms-dns1 211.136.20.203> <ms-dns2 211.136.17.107>]
rcvd [IPCP ConfReq id=0x1]
sent [IPCP ConfAck id=0x1]
rcvd [IPCP ConfAck id=0x2 <addr 10.115.59.42> <ms-dns1 211.136.20.203> <ms-dns2 211.136.17.107>]
Could not determine remote IP address: defaulting to 10.64.64.64
not replacing default route to eth0 [192.168.1.1]
local IP address 10.115.59.42
remote IP address 10.64.64.64
primary DNS address 211.136.20.203
secondary DNS address 211.136.17.107
Script /etc/ppp/ip-up started (pid 690)
Script /etc/ppp/ip-up finished (pid 690), status = 0x0
成功拨号之后, 将返回两个 DNS 服务器地址:
primary DNS address 211.136.20.203
secondary DNS address 211.136.17.107
2、将/etc/ppp/resolv.conf文件拷贝到/etc/下，用于DNS解析
nameserver DNS address 211.136.20.203
nameserver DNS address 211.136.17.107
3、添加路由 (如果本来没有其他网卡和路由表 [default], 可以直接上网, 不需要这步)
需要添加路由, 是因为, pppd 拨号时虚拟出了一个网卡, 我们要通过这个网卡来上网, 使用 ifconfig 命令, 可以看到多了一个网卡, 一般是 ppp0:
ppp0 Link encap:Point-to-Point Protocol
inet addr:10.186.110.45 P-t-P:10.64.64.64 Mask:255.255.255.255
执行以下命令
sudo route del default
sudo route add default dev ppp0
4、最后ping一下就可以上网了
参考链接：
【PPP 拨号上网步骤】