在使用ec20进行ppp拨号时，报错：Couldn’t open the /dev/ppp device: No such device or address，具体信息如下：
[17:19:14:826][hawk@Vimicro /etc/ppp/peers]#Couldn't open the /dev/ppp device: No such file or directory
[17:19:14:826]pppd: You need to create the /dev/ppp device node by
[17:19:14:840]executing the following command as root:
[17:19:14:840] mknod /dev/ppp c 108 0
[17:19:14:840]
[17:19:15:553]
[17:19:15:553][2]+ Done(4) pppd call unicom
[17:19:15:722][hawk@Vimicro /etc/ppp/peers]#
[17:19:15:929][hawk@Vimicro /etc/ppp/peers]#
[17:19:24:616][hawk@Vimicro /etc/ppp/peers]#mknod /dev/ppp c 108 0
[17:19:25:823][hawk@Vimicro /etc/ppp/peers]#pppd call unicom &
[17:19:25:874][hawk@Vimicro /etc/ppp/peers]#Couldn't open the /dev/ppp device: No such device or address
[17:19:25:874]pppd: Please load the ppp_generic kernel module.
[17:19:25:874]
[17:19:26:856]
[17:19:26:856][2]+ Done(4) pppd call unicom
根据报错信息Please load the ppp_generic kernel module.怀疑ppp驱动没有正确加载，然后在menuconfig中将ppp驱动全都勾选上。
问题解决。原因是缺少部分ppp驱动。