EHS6T USB port problem | Thales IoT Developer Community
April 21, 2016 - 1:21pm, 2740 views
We have a problem with EHS6T USB modem's USB port. The modem is connected to Raspberry PI 2. Sometimes modem hangs up totally. It may work work a day or two and then it hangs up again. I connected a monitor to the RPI to see what is going on and I saw that /dev/ttyACM0-6 devices were not visible. The modem and RPI is powered by 24V / 150W power.
- Reconnected the USB cable. No ttyACM -ports visible.
- Reset pulse to power connector pin 3. Modem won't reset!
- Rebooted the linux while modem was powered on. No ttyACM -ports visible
- Disconnected and reconnected modem's power cable while the linux was running and everything started to work ok.
We are using dozens of these modems and three or four has been malfunctioning. After replacing the faulty modem with a new one there has been no problems.
Linux version: Linux raspberrypi 3.18.11-v7+ #781 SMP PREEMPT Tue Apr 21 18:07:59 BST 2015 armv7l GNU/Linux
ATI1
Cinterion
EHS6
REVISION 03.001
A-REVISION 00.000.14
AT^SJAM=4
^SJAM: "a:/JRC-1.56.30.jad","Java Remote Control MIDlet Suite","Cinterion","1.56.30",1,703294,0
AT^SJAM=5
^SJAM: "a:/JRC-1.56.30.jad","Java Remote Control MIDlet Suite","Cinterion","1.56.30",1
Hello,
If I understand you well this USB port hanging problem was solved by replacing of the malfunctioning modules.
Or the modules were replaced for some other reason and you are looking for help for USB problem here?
Regards,
Bartłomiej
Hi,
The problem was solved by replacing the malfunctioning modems. I was curious if someone else have seen similar behaviour and maybe have a fix for it? I have one modem with older revision which has been online more than two years. I have also modems with the same version as the faulty one which are ok. The biggest problem is that you don't know beforehand if the modem is ok or not. Now we have added a relay which can turn off and on the modem if it freezes.
Hello,
If the modules were replaced and the new ones are working fine and you don't have more such issues with other modules that would suggest some hardware related problem. You are using the terminal version so it could have been module or terminal. Or maybe the power supply.
But I suspect that the power supply and software problem were excluded before the replacement. And the configuration was probably checked and compared to working modules and maybe firmware update performed.
The source of this problem doesn't look like something easy to discover so the relay seems to be a reasonable protection. But I hope it will never happen again.
Regards,
Bartłomiej