I can not make EDGE Connection by Hyper terminal. why?

[ahmad2005]

This is found in hyper terminal

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AT
OK
AT+CGDCONT=1,"IP","gprsunl"
OK
ATD*99***1#
CONNECT
 
CONNECT
 
CONNECT
 
CONNECT
 
CONNECT
 
CONNECT
 
CONNECT
 
NO CARRIER

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here why NO CARRIER occurs?





and this is found By serial port monitor during EDGE connection process while using modem plugin play soft ware to active the internet connection in PC.

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41 54 2B 43 47 44 43 4F 4E 54 3D 31 2C 22 49 50   AT+CGDCONT=1,"IP
 22 2C 22 67 70 72 73 75 6E 6C 22 0D               ","gprsunl".    
 
Answer: 4/28/2011 9:21:37 PM.54264 (+0.0000 seconds)
 
 0D 0A 4F 4B 0D 0A                                 ..OK..          
 
Port closed
 
Port opened by process "svchost.exe" (PID: 1300)
 
 0D 0A 4F 4B 0D 0A                                 ..OK..          
 
Request: 4/28/2011 9:21:38 PM.66764 (+0.0469 seconds)
 
 41 54 0D                                          AT.             
 
Answer: 4/28/2011 9:21:38 PM.66764 (+0.0000 seconds)
 
 0D 0A 4F 4B 0D 0A                                 ..OK..          
 
Request: 4/28/2011 9:21:38 PM.66764 (+0.0000 seconds)
 
 41 54 20 56 31 45 30 53 30 3D 30 0D               AT V1E0S0=0.    
 
Answer: 4/28/2011 9:21:38 PM.66764 (+0.0000 seconds)
 
 0D 0A 4F 4B 0D 0A                                 ..OK..          
 
Request: 4/28/2011 9:21:38 PM.68364 (+0.0156 seconds)
 
 41 54 53 37 3D 36 30 26 4B 33 0D                  ATS7=60&K3.     
 
Answer: 4/28/2011 9:21:38 PM.68364 (+0.0000 seconds)
 
 0D 0A 4F 4B 0D 0A                                 ..OK..          
 
Request: 4/28/2011 9:21:38 PM.69864 (+0.0156 seconds)
 
 41 54 53 30 3D 30 0D                              ATS0=0.         
 
Answer: 4/28/2011 9:21:38 PM.69864 (+0.0000 seconds)
 
 0D 0A 4F 4B 0D 0A                                 ..OK..          
 
Request: 4/28/2011 9:21:38 PM.74564 (+0.0469 seconds)
 
 41 54 0D                                          AT.             
 
Answer: 4/28/2011 9:21:38 PM.74564 (+0.0000 seconds)
 
 0D 0A 4F 4B 0D 0A                                 ..OK..          
 
Request: 4/28/2011 9:21:38 PM.76164 (+0.0156 seconds)
 
 41 54 20 56 31 45 30 53 30 3D 30 0D               AT V1E0S0=0.    
 
Answer: 4/28/2011 9:21:38 PM.76164 (+0.0000 seconds)
 
 0D 0A 4F 4B 0D 0A                                 ..OK..          
 
Request: 4/28/2011 9:21:38 PM.77664 (+0.0156 seconds)
 
 41 54 53 37 3D 36 30 26 4B 33 0D                  ATS7=60&K3.     
 
Answer: 4/28/2011 9:21:38 PM.77664 (+0.0000 seconds)
 
 0D 0A 4F 4B 0D 0A                                 ..OK..          
 
Request: 4/28/2011 9:21:38 PM.77664 (+0.0000 seconds)
 
 41 54 44 2A 39 39 2A 2A 2A 31 23 0D               ATD*99***1#.    
 
Answer: 4/28/2011 9:21:38 PM.79264 (+0.0156 seconds)
 
 0D 0A 43 4F 4E 4E 45 43 54 0D 0A                  ..CONNECT..     
 
[B]Port opened by process "svchost.exe" (PID: 1300)[/B]
 
Request: 4/28/2011 9:21:38 PM.93364 (+0.1406 seconds)
 
 7E FF 7D 23 C0 21 7D 21 7D 20 7D 20 32 7D 22 7D   ~ÿ}#À!}!} } 2}"}
 26 7D 20 7D 20 7D 20 7D 20 7D 25 7D 26 23 A9 5A   &} } } } }%}&#©Z
 7D 27 7D 27 7D 22 7D 28 7D 22 7D 2D 7D 23 7D 26   }'}'}"}(}"}-}#}&
 7D 31 7D 24 7D 26 4E 7D 33 7D 37 7D 21 D8 26 97   }1}$}&N}3}7}!Ø&?
 A7 8D BC 4E B2 BF DB A1 7D 2B BB 6C 97 FE 7D 20   §¼N²¿Û¡}+»l?þ} 
 7D 20 7D 20 7D 20 8B 7D 3D 7E                     } } } ?}=~

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Here "Port opened by process "svchost.exe" (PID: 1300)" what does that means? what is the working principle of "svchost.exe" ? if want to connect my modem microcontroller that time i do not get "svchost,exe" in microcontroller what should i do that time ?

 

[FvM]

It's completely unclear what you want to achieve. After connecting to the GPRS access point, you have to talk to it using the PPP protocol and connect the various TCP/IP network layers. You don't, so the server disconnects after a while.

In a regular dial-in connection, this is achieved by the Windows PPP driver. svchost.exe is the a system application loading various service dlls in Windows OS, e.g. the respective network service.

You can use wireshark to monitor what happens after "CONNECT". There are also Windows log options, that can be activated by registry settings.

 

[luben111]

According to Microsoft: “svchost.exe is a generic host process name for services that run from dynamic-link libraries. In your case you ran a modem and this is loading dynamically some functionality (you can see several commands sent automatically according to the build in protocol).

Your NO_CARRIER message appears because you probably don't send all required AT commands:
1. AT+CGDCONT=1,"IP","gprsunl"
2. AT
3. AT V1E0S0=0
4. ATS7=60&K3
5. ATS0=0
... etc.

 

[ahmad2005]

@FvM,
I understand. but problem is that there is no "PPP" protocol in Micro-controller, when i try to browse a particular web file by micro-controller what should i do that time ?

@luben111,
thanks for your information, "No CARRIER" is not the problem of that which you mention, i think problem may be in "PPP" and it do not open.

 

[FvM]

Some gprs modems have also built-in TCP/IP stacks, that allow to communicate through slected TCP protocols without using PPP, check the your modem documentation. Otherwise, you have to implement a full PPP and TCP/IP stack in your microcontroller. You'll find example implementation from several uC and compiler vendors, e.g. Microchip. But it's a complex task anyway.

 

[ahmad2005]

@FvM,
Many thanks. I got it.
I think, my modem have not built-in TCP/IP Stack. It's a Chines modem usually use for internet in PC and also it has no documentation or user manual.
Can you help me how can i implement PPP and TCP/IP stack in micro-controller ? Do you have any example or where can i find any idea ?