PPP problem with PLS62W | Telit Cinterion IoT Developer Community
March 23, 2021 - 2:58am, 2514 views
Hi there
Earlier I have established a PPP connection using PH8 modem. Now I am trying to make it work with PLS62W using 4G sim, but having trouble doing it.
I am able to talk to the modem with no issues while sending AT commands
After the modem receives ATD*99***1#, I get CONNECT as response
When the modem receives LCP request, I get an acknowledgment as a response from the modem but when the modem receives PAP request, I do not get any response.
How to resolve it?
Cheers
Hello,
Please try to use AT^SGAUTH command to configure the authentication type before the connection attempt.
Regards,
Bartłomiej
Thank you for getting back.
I do set AT^SGAUTH=1,1 to be used with PAP before attempting the connection.
Network provider has told me that there is no Username or Password required to register a session with the network.
Please let me know.
Cheers
Hello,
So you do set SGAUTH and it does not help. Can you give us more information about your setup? What OS or PPP stack do you use? What AT commands are sent and how PPP exchange look like? You wrote that there is no response from the module - for how long the application is waiting and what it does then?
Regards,
Bartłomiej
Hi there
I am trying to use this modem in our monitoring unit which does not run any OS. I am trying to mimic PPP stack in the firmware to establish a TCP connection.
These are the following commands send to the modem in the order:
1) ATE0
2) AT^SXRAT=3,3
3) AT^SCFG="GPIO/MODE/DCD0","gpio"
4)AT^SCFG="GPIO/MODE/DTR0","gpio"
5) AT^SCFG="GPIO/MODE/SYNC","std"
6) AT^SLED=2
7)AT^SCFG="GPRS/AutoAttach","enabled"
8) AT^SGAUTH=1,1
9)AT^SPOW?
10) AT^SPOW=1,0,0
11)AT+CPIN?
12)AT+CPIN ="****"
13) AT+CLCK="SC",2
14) AT+CSQ
15)AT+CIMI
16) AT+CGDCONT=1,"IP","m2m"
17) AT+CGATT=1
18)AT+CGACT=1,1
19) AT^SICA=1,1
20) AT^SISX="HostByName",1,"***.***.com"
21) AT^SICA=0,1
22) AT+CREG?
23) AT+COPS?
24)AT^SMONI where i get to know whether modem is connected to 3G/4G.In my case 4G
25) ATD*99**1#
Once application gets CONNECT as response,
26) application sends LCP Request packet 7E FF 7D 23 C0 21 7D 21 7D 20
7D 20 7D 30 7D 22 7D 26 7D 20
7D 20 7D 20 7D 20 7D 25 7D 26
7D 21 7D 22 7D 23 7D 24 31 7D
3A 7E
here modem sends backs the data to the application
27 )Again application sends LCP Request with the magic number,
7E FF 7D 23 C0 21 7D 21 7D 21
7D 20 7D 3C 7D 21 7D 24 7D 25
96 7D 22 7D 26 7D 20 7D 20 7D
20 7D 20 7D 23 7D 24 C0 23 7D
25 7D 26 3D C9 D6 34 7D 27 7D
22 7D 28 7D 22 C9 7D 3C 7E
28) Again application sends LCP Configure acknowledge
7E FF 7D 23 C0 21 7D 22 7D 20
7D 20 7D 30 7D 22 7D 26 7D 20
7D 20 7D 20 7D 20 7D 25 7D 26
7D 21 7D 22 7D 23 7D 24 7D 30
80 7E
then application gets acknowledgement from modem.
7E FF 7D 23 C0 21 7D 22 7D 21
7D 20 7D 38 7D 22 7D 26 7D 20
7D 20 7D 20 7D 20 7D 23 7D 24
C0 23 7D 25 7D 26 3D C9 D6 34
7D 27 7D 22 7D 28 7D 22 9B 25
7E
29) application sends pap request 7E FF 7D 23 C0 23 7D 21 7D 21
7D 20 7D 26 7D 20 7D 20 81 29
7E
after which no response from the modem and The above step 29 keeps on repeating and after 90 seconds, I send +++ that leads to code terminate request with terminate ack.
Hope this info helps.
Cheers
Akilesh
Hello,
I probably don't have the proper tool to decode your packets. But if the network does not require authentication you could also set no authentication with AT^SGAUTH and not send PAP request at all. At least for test.
I tried PPP in Windows and in my case it worked every time with any authentication configuration. In case of no authentication set with SGAUTH there was no authentication reqest sent. I think that what you could do is to setup PPP in Windows or Linux, sniff the PPP exchange and compare with what you do in your system.
As you are not using any ready and tested PPP stack it is also possible that there is some other problem in the unreplied packet not directly related to PAP.
Regards,
Bartłomiej
Thank you. Will get back to you with more findings soon.