第一步配置 pots 拨号对等 1：
hostname sanjose
dial-peer voice 1 pots
destination-pattern +111....
port 1/0/0
配置 pots 拨号对等 2：
dial-peer voice 2 pots
destination-pattern +111....
port 1/0/1
配置 voip 拨号对等 3：
dial-peer voice 3 voip
destination-pattern +111....
session target ipv4:172.16.65.182
配置E&M 端口：
voice-port 1/0/0
signal immediate
operation 4-wire
type 2
voice-port 1/0/1
signal immediate
operation 4-wire
type 2
配置串行端口:
interface serial 0/0
description serial interface type dce (provides clock)
clock rate 2000000
ip address 172.16.1.123
no shutdown
关于PBX部分
先配置好PBX，保证DTMF信号传输到Router