PPP GPRS on Pic18F452

[puppie7777]

Hi,
i am developing an application on Pic18F452 which need to build in PPP to connect to the internet through GPRS.
Now i can get the ACK of PAP from the GPRS modem (with a "welcome" word), but instead of responsing me an IPCP config request, the modem responsed me Terminating Request of LCP twice (two times for different ID), after that followed one request for config of PAP, and then come out with an error message: +CME ERROR: 133 and then NO CARRIER ... ...
Below is the sinffer data on my Rx pin (Rs232), anybody got any good suggestion will be highly appreciated!
00 FF
0D 0A 4F 4B 0D 0A 0D 0A 4F 4B 0D 0A 0D 0A 4F 4B
0D 0A 0D 0A 4F 4B 0D 0A 0D 0A 43 4F 4E 4E 45 43
54 20 31 31 35 32 30 30 0D 0A
(response of modem GPRS initialization)

7E
FF 7D 23 C0 21
7D 21 7D 21 7D 20 7D 36
7D 21 7D 24 7D 25 DC
7D 22 7D 26 7D 20 7D 20 7D 20 7D 20
7D 27 7D 22
7D 28 7D 22
7D 23 7D 24 C0 23
26 B4
7E
(LCP resuest)


7E
FF 7D 23 C0 21
7D 21 7D 22 7D 20 7D 28 7D 23 7D 24 C0 23
23 EB
7E

7E
FF 7D 23 C0 21
7D 22 7D 22 7D 20 7D 29 7D 23 7D 25 C0 23 7D 25
30 7A
7E

7E
FF 7D 23 C0 21
7D 21 7D 22 7D 20 7D 28 7D 23
7D 24 C0 23
23 EB
7E

7E
FF 7D 23 C0 23
7D 21 7D 21 7D 20 7D 33 7D 28 6A 6F 68 6E 5F 64 6F 65 7D 25 64 75 6D 6D 79 7D
26 A2
7E (PAP Request)

7E
FF 7D 23 C0 23
7D 22 7D 23 7D 20 7D 2D 7D 28
57 65 6C 63 6F 6D 65 21
BF 5D
7E (PAP ACK with Welcome! word)

(by right, from now should response me IPCP request ... ...)

7E
FF 7D 23 C0 21 7D 25 7D 23 7D 20 7D 24 85 72
7E (LCP Terminating Req)

7E
FF 7D 23 C0 21 7D 25 7D 24 7D 20 7D 24 80 FE
7E (LCP Terminating Req)

7E
FF 7D 23 C0 23 7D 21 7D 21 7D 20 7D 33 7D
28 6A 6F 68 6E 5F 64 6F 65 7D 25 64 75 6D 6D 79 7D 26 A2
7E (PAP Config Req)

7E
FF 7D 23 C0 21 7D 25 7D 25 7D 20 7D 24 5C A4
7E 7E FF 7D 23 C0 23 7D 21 7D 21 7D 20 7D 33 7D
28 6A 6F 68 6E 5F 64 6F 65 7D 25 64 75 6D 6D 79
7D 26 A2
7E

7E
FF 7D 23 C0 23 7D 21 7D 21 7D 20 7D 33 7D 28
6A 6F 68 6E 5F 64 6F 65 7D 25 64 75 6D 6D 79 7D
26 A2
7E

0D 0A 2B 43 4D 45 20 45 52 52 4F 52 3A
20 31 33 33 0D 0A 0D 0A 4E 4F 20 43 41 52 52 49
45 52 0D 0A
(+CME Error: 133 ... NO CARRIER...)

Thx!

[ckielstra]

Your question has nothing to do with the PIC processor or the CCS compiler. I suggest you ask this question in another forum where you will find more experts in your subject.

[puppie7777]

Thanks for your reply. i am just hoping that there's other people who also developing similar application, maybe they got some experience ... ...

[djpark]

It is Off-Topic indeed, but I sense you lost hope, so...

The typical reason for such error is caused by auth error, commonly the GSM/GPRS module is insisting on CHAP while you are expecting PAP for auth.

If you are using a Siemens module or phone, "at^sgaith=1" to force PAP may help.

-- dj

[puppie7777]

Thanks so much for djPark!

I have solved the problem, it is due to my GPRS isp, they changed the AT command. now my ppp connection works fine.

Thx!