Modem Disconnecting

Sierra Wireless AirPrime Modem Card Topics
Brady_ls
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Joined: Fri Mar 30, 2018 12:55 pm

Modem Disconnecting

Post by Brady_ls » Sat Apr 14, 2018 5:01 pm

Hi All,

My connection keeps dropping out. Below is a copy paste of my log. Does this mean that the modem is disconnecting from the router, or that modem is disconnecting from the network?

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Sat Apr 14 21:02:20 2018 : Modem #1 Connected (Sierra_Wireless,_Incorporated Sierra_Wireless_MC7455_Qualcomm®_Snapdragon™_X7_LTE-A)
Sat Apr 14 21:03:23 2018 : Disconnect (Removed) Modem #1
Sat Apr 14 21:03:46 2018 : Attempting to Connect Modem #1 (Sierra_Wireless,_Incorporated Sierra_Wireless_MC7455_Qualcomm®_Snapdragon™_X7_LTE-A)
Sat Apr 14 21:03:51 2018 : Modem #1 Connected (Sierra_Wireless,_Incorporated Sierra_Wireless_MC7455_Qualcomm®_Snapdragon™_X7_LTE-A)
Sat Apr 14 21:04:29 2018 : Disconnect (Removed) Modem #1

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JimHelms
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Re: Modem Disconnecting

Post by JimHelms » Sat Apr 14, 2018 5:08 pm

It appears to be connecting and immediately disconnecting.

First, make sure the correct APN is entered in MODEM >> CONNECTION INFO >> APN and there are no blank spaces behind the APN.

Next, go to MODEM >> DEBUG INFORMATION >> AT COMMANDS and copy and paste what it is showing.

Brady_ls
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Re: Modem Disconnecting

Post by Brady_ls » Sat Apr 14, 2018 6:24 pm

I tried re-flashing firmware and Configuring the MC7455. Same issue, but here is connection log and debug info from after ding this.

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Sat Apr 14 22:40:29 2018 : Modem #1 Connected (Sierra_Wireless,_Incorporated Sierra_Wireless_MC7455_Qualcomm®_Snapdragon™_X7_LTE-A)
Sat Apr 14 22:41:10 2018 : Disconnect (Removed) Modem #1
Sat Apr 14 22:41:31 2018 : Attempting to Connect Modem #1 (Sierra_Wireless,_Incorporated Sierra_Wireless_MC7455_Qualcomm®_Snapdragon™_X7_LTE-A)
Sat Apr 14 22:41:37 2018 : Modem #1 Connected (Sierra_Wireless,_Incorporated Sierra_Wireless_MC7455_Qualcomm®_Snapdragon™_X7_LTE-A)
Sat Apr 14 22:44:13 2018 : Disconnect (Removed) Modem #1

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Sat Apr 14 22:45:10 2018 : /dev/ttyUSB1 AT+CGDCONT?
+CGDCONT: 1,"IPV4V6","r.ispsn","0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0",0,0,0,0
OK
  
Sat Apr 14 22:51:28 2018 : /dev/ttyUSB1 AT+CGDCONT?
+CGDCONT: 1,"IPV4V6","r.ispsn","0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0",0,0,0,0
OK
  
Sat Apr 14 23:18:36 2018 : /dev/ttyUSB1 AT+CGDCONT?
+CGDCONT: 1,"IPV4V6","r.ispsn","0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0",0,0,0,0

Cheburashka
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Joined: Sun Apr 15, 2018 1:39 am

Re: Modem Disconnecting

Post by Cheburashka » Sun Apr 15, 2018 1:55 am

I am having the same issue. I'm totally clueless at this point as to what is happening. I know the router is working - if I plug in a USB hotspot into it, it connects, but it doesn't connect with the MC7455. Had random disconnects, now did a full reset of both router and MC7455 and not being connected at all. GSTATUS shows status as online:

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AT!GSTATUS?
!GSTATUS: 
Current Time:  681		Temperature: 39
Reset Counter: 1		Mode:        ONLINE         
System mode:   LTE        	PS state:    Not attached 
LTE band:      B26    		LTE bw:      5 MHz   
LTE Rx chan:   8763		LTE Tx chan: 4294967295
LTE CA state:  NOT ASSIGNED
EMM state:     Deregistered   	Attach Needed  
RRC state:     RRC Idle       
IMS reg state: No Srv  		

PCC RxM RSSI:  -85		RSRP (dBm):  -106
PCC RxD RSSI:  -80		RSRP (dBm):  -101
Tx Power:      0		TAC:         5412 (21522)
RSRQ (dB):     -6.5		Cell ID:     0A814E0B (176246283)
SINR (dB):     19.4
Log is similar to yours:

T

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ue Oct 17 17:47:33 2017 : Attempting to Connect Modem #1 (Sierra_Wireless,_Incorporated Sierra_Wireless_MC7455_Qualcomm®_Snapdragon™_X7_LTE-A)
Tue Oct 17 17:48:42 2017 : Attempting to Connect Modem #1 (Sierra_Wireless,_Incorporated Sierra_Wireless_MC7455_Qualcomm®_Snapdragon™_X7_LTE-A)
Tue Oct 17 17:50:26 2017 : Attempting to Connect Modem #1 (Sierra_Wireless,_Incorporated Sierra_Wireless_MC7455_Qualcomm®_Snapdragon™_X7_LTE-A)
Tue Oct 17 18:03:49 2017 : Disconnect (Removed) Modem #1
Tue Oct 17 18:05:26 2017 : Attempting to Connect Modem #1 (Sierra_Wireless,_Incorporated 

Cheburashka
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Re: Modem Disconnecting

Post by Cheburashka » Sun Apr 15, 2018 2:08 am

I have also put the SIM card in the hotspot it came with (Sprint/Calyx) and LTE is working fine.

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JimHelms
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Re: Modem Disconnecting

Post by JimHelms » Sun Apr 15, 2018 7:17 am

Brady_ls wrote:
Sat Apr 14, 2018 6:24 pm
I tried re-flashing firmware and Configuring the MC7455. Same issue, but here is connection log and debug info from after ding this.

Sat Apr 14 23:18:36 2018 : /dev/ttyUSB1 AT+CGDCONT?
+CGDCONT: 1,"IPV4V6","r.ispsn","0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0",0,0,0,0
The logs you posted really does not tell much other than showing r.ispsn is the APN you are trying to connect to the network with. Need to copy and past the reset of the information with the antenna signals that will be in that same window.

I also assume your APN is r.ispsn on your hotpot as opposed to n.ispsn?

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JimHelms
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Re: Modem Disconnecting

Post by JimHelms » Sun Apr 15, 2018 8:11 am

Cheburashka wrote:
Sun Apr 15, 2018 1:55 am
I am having the same issue. I'm totally clueless at this point as to what is happening.

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JimHelms
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Re: Modem Disconnecting

Post by JimHelms » Sun Apr 15, 2018 8:16 am

There is a step by step tutorial HERE to troubleshoot disconnects. It covers the vast majority of these type of issues. And it is most always something simple being overlooked.

Cheburashka
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Re: Modem Disconnecting

Post by Cheburashka » Sun Apr 15, 2018 5:02 pm

Hi Jim, you're totally right. One of the pigtails wasn't attached well to the MC7455, which explains the periodic signal drops.

Argh, spend 2 hours last night trying to diagnose/fix when it was something this simple!

Thanks again!
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JimHelms (Sun Apr 15, 2018 6:41 pm)

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JimHelms
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Re: Modem Disconnecting

Post by JimHelms » Sun Apr 15, 2018 6:40 pm

Cheburashka wrote:
Sun Apr 15, 2018 5:02 pm
Argh, spend 2 hours last night trying to diagnose/fix when it was something this simple!
That is often the case. Glad you got it up and running.

Again, I encourage anyone having disconnection issues to go through the check list on the tutorial. Chances are, it is there you will discover your fix.

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