Scripts/cambio_IP.sh

#!/bin/sh

# comtrend vr3025u
IFACE=ppp0.1

# vr3025un
#IFACE=ppp1

USER=admin
PASS=calandraca
IP=192.168.1.1

( sleep 3
  echo $USER
  sleep 1
  echo $PASS
  sleep 1
  echo ppp config $IFACE down
  sleep 5  
  echo ppp config $IFACE up
  sleep 5
  echo exit ) | telnet $IP