SDAA112 September   2025 AM625

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Use Case
  5. 2Platform and Products
    1. 2.1 Hardware
    2. 2.2 Software
  6. 3Methods
  7. 4Overview of Steps to Bring Up the Interface and Establish A Connection
  8. 5Troubleshooting
    1. 5.1 Power and Initialization First
    2. 5.2 Verify Network Before PPP
    3. 5.3 Test Manual Dial First
    4. 5.4 Timing When Dialing Up
    5. 5.5 Serial Communication
    6. 5.6 Chat Script
    7. 5.7 PPP Options
    8. 5.8 Signal Strength and Antenna Setup
    9. 5.9 Modem Reset
  9. 6Summary
  10. 7References

5.4 Timing When Dialing Up

When transitioning from modem configuration to PPP negotiation, timing is critical. The PPP daemon must attach immediately after the modem enters PPP mode. Manually issuing AT commands from a terminal and then switching to launch pppd often fails due to race conditions. Instead, use a chat script to automate the configuration and dialing sequence; this makes sure that the PPP attaches seamlessly.