The Industrial Raspberry Pi Forum

Hello Kunbus team,

We have a problem having USB modem that connects to cellular network with SIM card slot recognized by builtin Raspbian OS on RevPi Connect 2019-03-14-revpi-stretch. The device is recognized by ttyUSB0 and ttyUSB1 with Raspbian OS on regular Raspberry Pi, and we expect the same on RevPi. However, those two are already taken without physically connected devices. Is there a way to release these names without breaking the existing structure?

Someone posted similar in the context of Modbus and mine may be related. None of the services that depend on ttyUSB0/ttyUSB1 are being used from our application I believe.

This is the snapshot of /dev/tty* before/after hooking up the device (basically no difference which shouldn't be).
Best,
- Josh

The RevPi Connect has two built-in USB serial adapters, one for the RS485 port on the front and one for RS232 on the ConBridge. Those are the /dev/ttyUSB0 and /dev/ttyUSB1 devices that you're seeing.

If your modem exposes two USB serial adapters as well, those should appear as /dev/ttyUSB2 and /dev/ttyUSB3. Since they're not visible, my first guess is that your modem needs a driver which is missing in our kernel 4.9 package. Could you post the output of "lsusb" with the modem plugged in to verify that theory? Based on the USB vendor/device IDs of your modem I can verify if there's a driver in our kernel 4.9.

We'll release a kernel 4.19 in a few days, I can check if it contains a driver or whether we'll have to specifically enable the driver in the kernel configuration.

Hi lukas,

Sorry for the late reply.
We shipped the only Rev Pi to a field test and we have no device with us. We ordered the same device and is on the way. Will let you know when that's ready. Hopefully that device driver will make it in the next release.

Best,
- joshnn