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EHS6T USB port problem | Telit Cinterion IoT Developer Community

April 21, 2016 - 1:21pm, 3196 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





A-REVISION 00.000.14



^SJAM: "a:/JRC-1.56.30.jad","Java Remote Control MIDlet Suite","Cinterion","1.56.30",1,703294,0



^SJAM: "a:/JRC-1.56.30.jad","Java Remote Control MIDlet Suite","Cinterion","1.56.30",1