We have a fleet of Panasonic CF-53 MK4 laptops with Sierra Wireless EM7355 air cards. We recently switched from using external USB GPS pucks to using the EM7355’s internal GPS receiver for our vehicle tracking software. After the switch over, we began experiencing issues where the vehicles would random disappear off the tracking map. All the laptops are running Windows 10 v20H2 and the tracking software accesses the GPS via the NMEA COM port.
After doing some troubleshooting in these laptops, I found that the COM port was randomly closing and would only reinitialize once either the tracking software or the laptop restarted. I found that the reason the COM port was closing was because the card itself was rebooting as the uptime timer in AT!GSTATUS was being reset. So far, the only way that I have found to reset this timer is using AT!RESET or power cycling the card. I have tested this issue on both the Panasonic recommended driver and the latest driver offered by Sierra Wireless and got the same results.
At this point, I’m out of ideas on where to go next. Does anyone know of a solution to this problem?
AT!GSTATUS?
!GSTATUS:
Current Time: 267 Temperature: 36
Bootup Time: 5 Mode: ONLINE
System mode: LTE PS state: Attached
LTE band: B13 LTE bw: 10 MHz
LTE Rx chan: 5230 LTE Tx chan: 23230
EMM state: Registered Normal Service
RRC state: RRC Connected
IMS reg state: Full Srv IMS mode: Normal
RSSI (dBm): -32 Tx Power: 0
RSRP (dBm): -55 TAC: A3F4 (41972)
RSRQ (dB): -6 Cell ID: 0FC45CE9 (264527081)
SINR (dB): 30.0
AT!CUSTOM?
!CUSTOM:
CMCLIENT 0x01
GPIOSARENABLE 0x01
GPSENABLE 0x04
GPSSEL 0x01
NMEAENABLE 0x01
GOBIIMEN 0x01
GMMCAUSE7REMAP 0x01
USBSERIALENABLE 0x02
AT!GOBIIMPREF?
!GOBIIMPREF:
preferred fw version: 05.05.58.01
preferred carrier name: VZW
preferred config name: VZW_005.029_000
current fw version: 05.05.58.01
current carrier name: VZW
current config name: VZW_005.029_000
AT!GVER?
!GVER: SWI9X15C_05.05.58.01 r27044 carmd-fwbuild1 2015/03/05 00:02:40
AT!GVERBT?
!GVERBT: SWI9X15C_05.05.58.01 r27044 carmd-fwbuild1 2015/03/05 00:02:40
AT!HWID?
Revision: 1.1
AT!PACKAGE?
1102038_9903061_EM7355_05.05.16.02_00_PanasonicNotebook_005.002_000
AT!PCINFO?
State: Online
LPM force flags - W_DISABLE:0, User:0, Temp:0, Volt:0, BIOS:0, GOBIIM:0
W_DISABLE: 0
Poweroff mode: 0
LPM Persistent: 0
AT!PRIID?
PRI Part Number: 9903061
Revision: 05.02
Carrier PRI: 9999999_9902196_SWI9X15C_05.05.16.00_00_ATT_005.009_000
Carrier PRI: 9999999_9902574_SWI9X15C_05.05.16.00_00_GENNA-UMTS_005.007_002
Carrier PRI: 9999999_9902350_SWI9X15C_05.05.37.00_00_SPRINT_005.018_002
Carrier PRI: 9999999_9902266_SWI9X15C_05.05.58.01_00_VZW_005.029_000
AT!UDINFO?
VID: 0x1199
APP PID: 0x9041
BOOT PID: 0x9040
Interface: QBI
Manufacturer: Sierra Wireless, Incorporated
Product: EM7355
AT!UDPID?
!UDPID:
APP : 9041
BOOT: 9040
AT!UDUSBCOMP?
!UDUSBCOMP: 8