The specific implementation process of GPRS and Internet data communication through PPP Dialing:
1. the echo of the GPRS module is disabled, and the MCU sends ateov1 to the GPRS module.
2. Complete the access initialization: At + cgdcont = 1, "ip", and "cmnet ".
3. Call cmnet: ATD * 99 *** 1 #.
4. moden returns the correct cennect information.
5. The terminal actively sends LCP data packets (req, ack, reject) for Link negotiation, which may vary depending on the server ISP provider.
ISP option. If the terminal does not receive the request, a reject is returned.
The server's ISP does not need to reject the reject when sending an LCP (request) terminal ack;
Ack is sent when either party accepts the request and does not process the Nak data packet
If the link is unavailable, it will be sent again ( Program And MCU mechanism) until the connection is successful
6. the LCP configuration has successfully entered pap authentication. Currently, China Mobile uses a plaintext password to authenticate the identity. The authentication completes identity authentication by reading SIM card information and identifying the user name and password by phone number, therefore, the data packet sending the user name and password can be null.
7. After the PAP passes, IP coordination configuration (ipcp) is required. If option 3 is configured (IP address), the gateway and DNS configuration information can be omitted. Send the Nak Option 3 configuration and send it to the server at 00.00.00.00, returns the current IP address of the terminal,
Whether this IP address is available depends on the cmnet settings.
If cmnet Disables direct routing within the LAN, Ping tests can be performed in PC + GPRS mode.
Otherwise, you must map and convert the IP addresses and ports before communication.
8. After ipcp is passed, you must have the relevant NCP protocol for network layer protocol selection TCP/IP or UDP for data transmission. In this solution, you do not need to consider the relevant network-layer data transmission protocols.
9. Mode Conversion: The grrs data mode without interrupting the connection-use the ++ command to switch the AT command status. If the data status is switched back, enter ato to the cms91 gpprs module.
10. Disconnect the PPP connection of GPRS. You can use the LCP package to complete the connection // or use the AT command state ath command to end up the current connection.
11. When GPRS is connected to the Internet and the channel is communicating, no external call will respond.
If there is no data transmission, the call information can reach the GPRS module. Because the module is in the data status, the information can only be obtained through the ring foot without using multiplex, if the MCU processes a call, it can switch to the AT command status. |
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