jdubin
Posts: 12
Joined: Sun Jun 03, 2012 2:27 am

Trouble with USB "hardware" modem

Tue Feb 26, 2013 11:41 pm

Hi folks,

I'm using a 256MB model B running 2013-02-09-wheezy-raspbian. I've done apt-get update, apt-get upgrade, and rpi-update. I'm using a Rosewill RNX-56USB modem, which IDs itself as follows:

Code: Select all

[   96.022672] usb 1-1.3: new full-speed USB device number 5 using dwc_otg
[   96.102683] usb 1-1.3: device descriptor read/64, error -32
[   96.292707] usb 1-1.3: device descriptor read/64, error -32
[   96.482730] usb 1-1.3: new full-speed USB device number 6 using dwc_otg
[   99.045557] usb 1-1.3: New USB device found, idVendor=0572, idProduct=1321
[   99.045591] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[   99.045608] usb 1-1.3: Product: USB Modem
[   99.045622] usb 1-1.3: Manufacturer: Conexant
[   99.045635] usb 1-1.3: SerialNumber: 24680246
[  100.269716] cdc_acm 1-1.3:1.0: ttyACM0: USB ACM device
[  105.270746] usbcore: registered new interface driver cdc_acm
[  105.270777] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters
The problem is it doesn't respond to AT commands. Minicom, pointed to /dev/ttyACM0 at various rates, doesn't work. The goal is to get Hylafax working, and faxsetup doesn't see it respond either. What's frustrating is that I did have this working just a few weeks ago - but on a different SD card which has since been overwritten.

What am I missing?

Thanks for your help!

jdubin
Posts: 12
Joined: Sun Jun 03, 2012 2:27 am

Re: Trouble with USB "hardware" modem

Wed Feb 27, 2013 2:13 am

GRRRRRRR!!!!! Never underestimate the ability of a crappy cable to really mess things up!!!

It turns out it was all due to the USB cable used between the Raspi and the power supply! Mind you that the power supply is a champ (HP Touchpad [email protected])... but apparently the cheap USB cable I used is not. I'm really shocked that it worked seemingly fine up until the point where I tried to issue AT commands. Hmmph.

MaxK1
Posts: 1043
Joined: Sun Aug 26, 2012 11:34 pm

Re: Trouble with USB "hardware" modem

Wed Feb 27, 2013 11:48 am

Cables, connectors and power supplies. Grrr. Each can be a B****. Glad you found it.
You are in a maze of twisty little passages, all alike.
When General Failure and Major Disaster get together, Private Parts usually suffers.

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