# GPRS Connection Failure in Sierra SL Series Modems SL8082BT **URL:** \ **Category:** Uncategorized\ **Created:** [May 26, 2024, 7:20pm UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398 "2024-05-26T19:20:36Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![manojlakkavaram](https://avatars.discourse-cdn.com/v4/letter/m/ad7895/32.png) [@manojlakkavaram](https://forum.sierrawireless.com/u/manojlakkavaram)\ **Post date:** [May 26, 2024, 7:20pm UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/1 "2024-05-26T19:20:36Z")
We are using Sierra-based SL Series Modems (Open AT) for our energy meters to communicate data to a RabbitMQ Broker Queue. The data is received as RF Zigbee payload and then sent to RabbitMQ Queue . The modem performs several steps on power-up to establish a GPRS connection, including SIM registration and GPRS Barrier configuration. However, we are facing a recurring issue with the modems failing to obtain a SIM network IP, resulting in a **GPRS Connection Failure with error number -36** #### Observations: 1. **Error Description** : - The modem is unable to get a SIM network IP. - Error: GPRS Connection Failure, Error Code: -36. 1. **Field Deployment** : - 229 devices installed across various locations. - Approximately 10-15 devices go out of network weekly. - Devices often return to the network after a power reset or SIM replacement. 1. **Diagnostic Observations** : - Device A fails at location A but works when moved to location B. - Device B consistently works at its location and does not face network issues. - Issue persists despite multiple soft resets; sometimes resolves with a hard reset. - Devices with new SIM cards reconnected successfully within 72 hours. #### Request for Assistance: 1. **Potential Causes** : - What could be the underlying cause of the GPRS connection failure and the error code -36? 1. **Troubleshooting Steps** : - Are there any recommended steps for further diagnosing the issue? - Would firmware or hardware modifications potentially resolve these intermittent connectivity issues? Please do the needful. Thanks in Advance! ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [May 27, 2024, 1:11am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/2 "2024-05-27T01:11:16Z")
which FW are you using? for the bearer error: ![image](https://us1.discourse-cdn.com/flex025/uploads/sierrawireless/original/2X/e/e74e3d3a1f4839b0c39536f4520ada92af93b0c1.png) could it be related to SIM? Have you put the problematic SIM to another good device? ---
**Author:** ![manojlakkavaram](https://avatars.discourse-cdn.com/v4/letter/m/ad7895/32.png) [@manojlakkavaram](https://forum.sierrawireless.com/u/manojlakkavaram)\ **Post date:** [June 3, 2024, 5:06am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/3 "2024-06-03T05:06:31Z")
ati3 R7.54.0.A1.201603171313.SL8082BTR 1997208 031716 13:13 OK ati9 “DWL”," C04.05.14.00.SL8RDBT R2684 CNSHZ-ED-XP0031 2015/11/05 21:36:55",“”,“Sierra Wireless”,0,“”,“00000000”,“00000000” “FW”,“FW\_754\_0\_A1\_22\_1.SL808FAx”,“R7.54.0.A1.201603171313.SL8082BTR”,“Sierra Wireless”,1997208,“031716 13:13”,“a887779d”,“10002020” “MODEM 3G+”,“Revision: C04.05.14.00.SL8RDAP R2684 CNSHZ-ED-XP0031 2015/11/05 21:36:55” “OAT”,“”,“”,“”,215664,“081023 13:31”,“43df8f91”,“10700000” -“Developer Studio”,“3.6.0.201511091706” -“Open AT Application Framework package”,“2.54.2.A1.201702240946” -“Open AT OS Package”,“6.54.3.A1.201609080909” -“Firmware Package”,“7.54.2.A1.201701061226” -“ExtendedATApplication Library Package”,“3.2.0.A1.201610211044” -“eCall Library Package”,“1.3.4.201512300930” -“Local Trace Session Library Package”,“1.1.0.201410231018” -“Location Library Package”,“1.4.8.201509231354” -“AirVantage Agent Library Package”,“5.3.6.I201504101620” -“Security Library Package”,“2.2.4.201610061056” -“Internet Library Package”,“5.58.3.A1.201610210959” “ROM”,“8400000” “RAM”,“4000000” “OATRAM”,“b00000” “DWLNAME”,“SL808xA” OK at+wopen=2 +WOPEN: 2,“AT v06.54A1”,“AT v06.54A1” ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [June 3, 2024, 5:14am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/4 "2024-06-03T05:14:45Z")
could it be related to SIM? Have you put the problematic SIM to another good device? ---
**Author:** ![manojlakkavaram](https://avatars.discourse-cdn.com/v4/letter/m/ad7895/32.png) [@manojlakkavaram](https://forum.sierrawireless.com/u/manojlakkavaram)\ **Post date:** [June 3, 2024, 5:17am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/5 "2024-06-03T05:17:01Z")
## Error Log 2024- 3-20 0:50:56 WIP\_BEV\_CONN\_FAILED,11,-36 2024- 3-20 0:50:56 default Soft\_Reset 2024- 3-21 18:19:48 wdt\_return\_value = 0 2024- 3-21 18:19:48 ADL\_INIT\_POWER\_ON 2024- 3-21 18:19:48 flhSubscribe ADL\_RET\_ERR\_ALREADY\_SUBSCRIBED 2024- 3-21 18:19:49 before GPRSInit() in poll\_creg\_callback 2024- 3-21 18:20:25 WIP\_BEV\_CONN\_FAILED,0,-36 2024- 3-21 18:20:35 before GPRSInit() in poll\_creg\_callback 2024- 3-21 18:20:35 The device is already opened If we use the same SIM card in another modem its working Fine, we are using STATIC IP based SIM cards which means IP will never change. but before getting this error SIM connected to GPRS and it working fine, after some days or some time we are getting this -36 error message. ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [June 3, 2024, 5:19am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/6 "2024-06-03T05:19:13Z")
as a workaround, you can do software reset when receiving this error ---
**Author:** ![manojlakkavaram](https://avatars.discourse-cdn.com/v4/letter/m/ad7895/32.png) [@manojlakkavaram](https://forum.sierrawireless.com/u/manojlakkavaram)\ **Post date:** [June 3, 2024, 5:19am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/7 "2024-06-03T05:19:56Z")
> [@jyijyi](#): > > software reset when receiving this error Yes we are doing that, by giving at+cfun=1, but still no result. ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [June 3, 2024, 5:28am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/8 "2024-06-03T05:28:01Z")
what do you mean by “no result”? ---
**Author:** ![manojlakkavaram](https://avatars.discourse-cdn.com/v4/letter/m/ad7895/32.png) [@manojlakkavaram](https://forum.sierrawireless.com/u/manojlakkavaram)\ **Post date:** [June 3, 2024, 5:28am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/9 "2024-06-03T05:28:47Z")
Not Connecting to GPRS. ---
**Author:** ![manojlakkavaram](https://avatars.discourse-cdn.com/v4/letter/m/ad7895/32.png) [@manojlakkavaram](https://forum.sierrawireless.com/u/manojlakkavaram)\ **Post date:** [June 3, 2024, 5:32am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/10 "2024-06-03T05:32:48Z")
case WIP\_BEV\_CONN\_FAILED: wip\_bearerGetOpts(b, WIP\_BOPT\_ERROR, &wip\_error\_code,WIP\_BOPT\_END); sprintf(wip\_buff,“%s,%d,%d”,“WIP\_BEV\_CONN\_FAILED”,gprs\_conn\_fail,wip\_error\_code); adl\_atSendResponse ( ADL\_AT\_UNS, wip\_buff ); debuglog(wip\_buff); ``` //wip_bearerStop(b); //debuglog("wip_bearerStop @ WIP_BEV_CONN_FAILED"); //debuglog("WIP_BEV_CONN_FAILED"); gprs_conn_fail++; if (gprs_conn_fail >= 12) //15 min //2mins==12 assumed { ``` #if(D\_GPRS==1) adl\_fcmSendData((u8)FCM\_Handle,(u8 \*)“Restart due to CONN\_FAILED” ,strlen(“Restart due toCONN\_FAILED”)); #endif gprs\_conn\_fail=0; Soft\_Reset(); } uGPRSFlag = 0; c = NULL; #if(D\_GPRS==1) //adl\_fcmSendData((u8)FCM\_Handle,(u8 \*)“WIP\_BEV\_CONN\_FAILED OK\r\n”,20); adl\_fcmSendData((u8)FCM\_Handle,(u8 \*)wip\_buff,strlen(wip\_buff)); #endif adl\_tmrUnSubscribe (blinkled,meter\_io ,ADL\_TMR\_TYPE\_100MS ); blinkled = adl\_tmrSubscribe ( TRUE, 20, ADL\_TMR\_TYPE\_100MS, meter\_io ); adl\_tmrSubscribe(FALSE, (CREG\_TMR\_SEC \* 10), ADL\_TMR\_TYPE\_100MS,poll\_creg); break; ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [June 3, 2024, 5:40am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/11 "2024-06-03T05:40:27Z")
I think you don’t need to wait for 12 times ---
**Author:** ![manojlakkavaram](https://avatars.discourse-cdn.com/v4/letter/m/ad7895/32.png) [@manojlakkavaram](https://forum.sierrawireless.com/u/manojlakkavaram)\ **Post date:** [June 3, 2024, 5:43am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/12 "2024-06-03T05:43:20Z")
Its not 12 Times, we are waiting for 2 mins to do the reset. after receiving the -36 error message. ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [June 3, 2024, 5:58am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/13 "2024-06-03T05:58:18Z")
then does it work??? ---
**Author:** ![manojlakkavaram](https://avatars.discourse-cdn.com/v4/letter/m/ad7895/32.png) [@manojlakkavaram](https://forum.sierrawireless.com/u/manojlakkavaram)\ **Post date:** [June 8, 2024, 8:13am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/14 "2024-06-08T08:13:03Z")
No The result is same “Getting Error 36”. ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [June 8, 2024, 8:21am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/15 "2024-06-08T08:21:57Z")
Can we restart the OpenAT application by AT+wopen=0 and AT+Wopen=1 ? ---
**Author:** ![manojlakkavaram](https://avatars.discourse-cdn.com/v4/letter/m/ad7895/32.png) [@manojlakkavaram](https://forum.sierrawireless.com/u/manojlakkavaram)\ **Post date:** [June 8, 2024, 8:29am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/16 "2024-06-08T08:29:09Z")
1. Already OpenAT application is running in modem, is there chance to stop and start the OpenAT application? 2. If it is there how can we implement in source to stop and start the application? 3. Can we get ant example or related links also fine. Thank you! ---
**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\ **Post date:** [June 8, 2024, 11:13am UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/17 "2024-06-08T11:13:44Z")
Q1: You can restart the application by AT+wopen=0 and AT+Wopen=1 Q2: no, you cannot, but at least you can know if issue solved by restarting openat application ---
**Author:** ![manojlakkavaram](https://avatars.discourse-cdn.com/v4/letter/m/ad7895/32.png) [@manojlakkavaram](https://forum.sierrawireless.com/u/manojlakkavaram)\ **Post date:** [June 8, 2024, 7:31pm UTC](https://forum.sierrawireless.com/t/gprs-connection-failure-in-sierra-sl-series-modems-sl8082bt/32398/18 "2024-06-08T19:31:41Z")
Ok will try this way. Thank you.