# USB to serial converter

## tank

I have a T40 laptop which does not have Serial ports, however I need a serial port.

I have a Belkin Usb - Serial port converter and compiled my kernel with the Belkin Usb Serial driver.

Question is how can I test it.  What /dev is it going to be assigned to?  I looked in /dev and there is no ttyS0 or and ttySx for that matter.

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## Minos

Did you build support for it in your kernel?  There's an option for serial converters in the USB section of menuconfig.  If you have (and loaded it if as a modules), then you might find the device in /dev/cua/, probably /dev/cua/0.

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## tank

Yes I did build support in my kernel

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## tank

This is the message I get when I unplug and plug in my usb->serial converter

```

tail -n 0 -f /var/log/messages

Aug  6 21:21:09 jgordon7-1 usb.c: USB disconnect on device 00:1d.1-2 address 4

Aug  6 21:21:15 jgordon7-1 hub.c: new USB device 00:1d.1-2, assigned address 5

Aug  6 21:21:15 jgordon7-1 usb.c: USB device 5 (vend/prod 0x50d/0x109) is not claimed by any active driver.

Aug  6 21:21:18 jgordon7-1 usb.agent: ... no modules for USB product 50d/109/102

```

this is the output of dmesg |grep usb

```

usb.c: registered new driver hub

usb.c: new USB bus registered, assigned bus number 1

usb.c: new USB bus registered, assigned bus number 2

usb.c: new USB bus registered, assigned bus number 3

usb.c: registered new driver hid

usb.c: registered new driver serial

usbserial.c: USB Serial support registered for Generic

usbserial.c: USB Serial Driver core v1.4

usbserial.c: USB Serial support registered for Belkin / Peracom / GoHubs USB Serial Adapter

```

So it looks like I may have the wrong driver compiled into the kernel.  Is that a correct assumtion from the above results?  Any one got an idea which driver I should be using?  All I know is it is a Single port Belkien Usb->Serial adapter, do not even see a model number on it.[/code]

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## volumen1

You might try building and loading the pl2303 module.  I've monkey'd around with usbserial a little bit on a Thinkpad T40 and I couldn't get /dev/usb/tts/0 to show up until I loaded pl2303.  I can't remember the brand of cable that I have, though.

However, this might not help you too much.  While I do have the /dev/usb/tts/0 device now, I can't really use it.  When I run minicom and then exit out, I get a segmentation fault.  If I try to use gpsd, it runs for awhile, but if I try to query it with gpsdrive or kismet or something like that, I get a segmentation fault or the machine locks up.

Crud.

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## volumen1

Woah, I take it back.  It was hotplug that was screwing it up.  I removed hotplug from my default runlevel and put usb-uhci, ecd-hcdi, usbserial and pl2303 in my /etc/modules.autoload.  I'm rocking now.  So, hopefully that will help you.

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## FourARSEDSheep

where can i find the pl2303 module?

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## DocGonzo

If you compiled it with your kernel, it should be in /lib/modules/x.x.x/kernel/drivers/usb/serial/pl2303.o. If it is not there, then look into the usb-devices/serial section in your kernelconfig. I am not at my linux pc so don't blame me if the paths are not that exactly   :Embarassed: 

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## tovarich

 *volumen1 wrote:*   

> You might try building and loading the pl2303 module.  I've monkey'd around with usbserial a little bit on a Thinkpad T40 and I couldn't get /dev/usb/tts/0 to show up until I loaded pl2303.  I can't remember the brand of cable that I have, though.
> 
> However, this might not help you too much.  While I do have the /dev/usb/tts/0 device now, I can't really use it.  When I run minicom and then exit out, I get a segmentation fault.  If I try to use gpsd, it runs for awhile, but if I try to query it with gpsdrive or kismet or something like that, I get a segmentation fault or the machine locks up.
> 
> Crud.

 I have been trying to get my Garmin Etrex to work with this Radioshack usb->serial converter  for a couple weeks and had no luck. Turns out the pl2303 module works great with it. Thanks!

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## foofoo

howdy,

I also have this delightful usb-to-serial adapter, lsusb lists is as:

```
Bus 005 Device 005: ID 050d:0109 Belkin Components F5U109/F5U409 PDA Adapter

```

After much soul searching and a visit to a FreeBSD page it seems the driver to use is the mct_u232.. 

With my 2.6.15-r7 kernel I set the following in /usr/src/linux/.config :

```
CONFIG_USB_SERIAL=m

...

CONFIG_USB_SERIAL_MCT_U232=m

```

(USB Serial could probably just be compiled into the kernel instead of as a module)

```
modprobe mct_u232
```

 provides the following dmesg | tail :

 *Quote:*   

> drivers/usb/serial/usb-serial.c: USB Serial support registered for MCT U232
> 
> mct_u232 5-1:1.0: MCT U232 converter detected
> 
> usb 5-1: MCT U232 converter now attached to ttyUSB0
> ...

 

/dev/ttyUSB0 exists and the device works..

 :Razz: 

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