title: pppd can't receive OK when using chat script
body: <p>I have a problem when using PPPD to dial a modem. </p>
  
  <p>Here is the file pppd_script I used.</p>
  
  <pre><code># Debug info from pppd
  debug
  #kdebug 4
  # Most phones don't reply to LCP echos
  lcp-echo-failure 3
  lcp-echo-interval 3
  # Keep pppd attached to the terminal
  # Comment this to get daemon mode pppd
  nodetach
  # The chat script (be sure to edit that file, too!)
  connect "/usr/bin/chat -V -s -f /etc/ppp/chat_script"
  # Serial Device to which the HSDPA phone is connected
  /dev/ttyO0
  # Serial port line speed
  115200
  dump
  # The phone is not required to authenticate
  #noauth
  # If you want to use the HSDPA link as your gateway
  defaultroute
  # pppd must not propose any IP address to the peer
  #noipdefault
  ipcp-accept-local
  ipcp-accept-remote
  # Keep modem up even if connection fails
  #persist
  # Hardware flow control
  crtscts
  # Ask the peer for up to 2 DNS server addresses
  usepeerdns
  # No ppp compression
  novj
  nobsdcomp
  novjccomp
  nopcomp
  noaccomp
  # For sanity, keep a lock on the serial line
  lock
  # Show password in debug messages
  show-password
  </code></pre>
  
  <p>And below are the chat_script</p>
  
  <pre><code>#!/system/bin/sh
  # Connection to the network
  '' AT+CGDCONT=1,"IP","telstra.internet"
  # Dial the number.
  OK ATD*99***1#
  # The modem is waiting for the following answer
  </code></pre>
  
  <p>When I run the command pppd file pppd_script,  the pppd command stuck at </p>
  
  <pre><code>send( AT+CGDCONT=1,"IP","telstra.internet" )
  expect(OK)
  </code></pre>
  
  <p>However, when I use the command below, I can get the OK.</p>
  
  <pre><code>echo "AT+CGDCONT=1,"IP","telstra.internet"" &gt;/dev/ttyO0
  </code></pre>
  
  <p>I recompiled the pppd and chat script, but still the same thing.</p>
  
  <p>What could be the reason for getting stuck?</p>