BG95-M3 Connection suspension with +++ and/or DTR line Toggle

Technical Subjects
1

Hi ,
I am using the BG95-M3 with firmware version BG95M3LAR02A03_01.012.01.012. We are connecting by establishing PPP Connection. Our connection with IPv6 is successful and we get and address from the network. However, we do need to periodically suspend our connection by switching to command mode and query some information.

We follow the procedure in the AT command manual to ensure that we do not send data one second before sending the +++ escape sequence. However, when every we send the +++ escape sequence, the connection is being terminated instead of being suspended.

Please see below:

*[Fri Jun 25 15:13:47.828 2021] CELL_PPP: PPP NETIF Status change detected*

  • [Fri Jun 25 15:13:47.828 2021] CELL_PPP: Unicast IPv6 Address: 2605:9780:1030:10DE:E88F:1068:E38A:F281 à We got connected*

  • [Fri Jun 25 15:13:47.828 2021] CELLMGR: NETWORK UP*

  • [Fri Jun 25 15:13:47.828 2021] 00 FE 80 00 00 00 00 00 00 00 00 00 46 0F B2 19 01 02 01 00 00 00 00 00 00 E4 9E 7E*

  • [Fri Jun 25 15:13:47.829 2021] pppos_input[0]: got 28 bytes*

  • [Fri Jun 25 15:13:47.829 2021] ppp_input[0]: ip6 in pbuf len=72*

  • [Fri Jun 25 15:13:53.856 2021]*

  • [Fri Jun 25 15:13:53.856 2021]*

  • [Fri Jun 25 15:13:53.856 2021] > à Waited over one second without sending data*

  • [Fri Jun 25 15:13:54.192 2021]*

  • [Fri Jun 25 15:13:54.192 2021] >linkstatus escp à We send the escape sequence*

  • [Fri Jun 25 15:14:07.492 2021]*

  • [Fri Jun 25 15:14:07.492 2021] CELL CMD: Tx Command: +++*

  • [Fri Jun 25 15:14:07.508 2021]*

  • [Fri Jun 25 15:14:07.508 2021] >*

  • [Fri Jun 25 15:14:07.796 2021] CELL CMD: Awaiting AT Command response*

  • [Fri Jun 25 15:14:08.099 2021]*

  • [Fri Jun 25 15:14:08.099 2021] CELL CMD: Awaiting AT Command response*

  • [Fri Jun 25 15:14:08.403 2021]*

  • [Fri Jun 25 15:14:08.403 2021] CELL CMD: Awaiting AT Command response*

  • [Fri Jun 25 15:14:08.691 2021] 0D 0A 4E 4F 20 43 41 52 52 49 45 52 0D 0A à modem response with “ NO CARRIER ” which indicates that connection was terminated instead of being suspended*

  • [Fri Jun 25 15:14:08.718 2021]*

  • [Fri Jun 25 15:14:08.718 2021] cellRxATCmdResp: Data Mode disconnected instead of being suspended*

  • [Fri Jun 25 15:14:08.718 2021]*

  • [Fri Jun 25 15:14:08.718 2021] CELL CMD: Tx Command: AT+QCSQ*

  • [Fri Jun 25 15:14:08.718 2021]*

  • [Fri Jun 25 15:14:09.045 2021] 0D 0A 2B 51 43 53 51 3A 20 22 65 4D 54 43 22 2C 2D 37 36 2C 2D 31 30 33 2C 38 39 2C 2D 31 34 0D 0A 0D 0A 4F 4B 0D 0A*

  • [Fri Jun 25 15:14:09.045 2021] RSSI: -76 dBm*

  • [Fri Jun 25 15:14:09.045 2021] RSRP: -103 dBm*

  • [Fri Jun 25 15:14:09.045 2021] SINR: 89 (-3 dB)*

  • [Fri Jun 25 15:14:09.045 2021] RSRQ: -14 dB*

  • [Fri Jun 25 15:14:09.045 2021] SIGLVL: Returning to Data mode*

  • [Fri Jun 25 15:14:09.046 2021] cellResumeConnection: Resume PPP Connection…*

  • [Fri Jun 25 15:14:09.046 2021]*

  • [Fri Jun 25 15:14:09.046 2021] CELL CMD: Tx Command: ATO à We try returning to data mode just to verify*

  • [Fri Jun 25 15:14:09.046 2021]*

  • [Fri Jun 25 15:14:09.046 2021] 0D 0A 4E 4F 20 43 41 52 52 49 45 52 à We get the same NO CARRIER from the modem indicating that the connection was terminated*

The same thing happens with toggling DTR line although we set the configuration to AT&D1.

Could someone kindly help share some insight on what could be the problem here>

Thanks,
Edman

2

for this datacall disconnection issue， we need to QXDM log for more analysis。

Please pay attention to the following points ：

image
image782×243 21.5 KB

for more supports ， we reach to support@quectel.com

3

There was an issue in the modem’s firmware with attempting to suspend IPv6 connection. The issue was fixed in a later release of the modem firmware beginning with BG95M3LAR02A03_01.014.01.014