External Modem help (USB to serial)

Forum: Networking
Topic: External Modem help (USB to serial)
started by: ShaneRay

Posted by ShaneRay on July 10 2005,14:11

Well, after trying for months to get my winmodem to work in linux, I gave up and ordered a USR external off of ebay. When it arrived, I was looking forward to getting up and running. So what happens? I find out my one and only serial port is dead...lol.

Anyway, I finally had no choice but to go out and purchase a USB to serial adapter (cheaper than a PCI serial card). It works great in XP, SuSE and Ubuntu. However, I can't get it to work in DSL.

DSL "appears" to communicate with it, but just exits the script in the end. The modem should be at /dev/ttyUSB0--that is the only location where the dail script does anything other than exit, so I assume it sees somthing there. I'm wondering if it's perhaps that the other distros are on the 2.6 kernal and DSL is on an updated 2.4??

Well, any insights would be appreciated.

Thanks

Posted by cbagger01 on July 10 2005,15:26

I doubt it.

Standard USB serial devices are not a new development.

Try to connect to your port using Microcom and type:

AT

to see if your modem responds with an OK

Posted by ShaneRay on July 12 2005,21:16

Thanks, cbagger.

After a couple of busy days, I'll give this a shot and see what happens.

I did notice in dmesg, however, that the serial port is being seen no problem and the drivers loaded. The system just won't communicate with the modem.

I'll run minicom and see...

Thanks

Posted by ShaneRay on July 12 2005,21:48

Well, Just ran Microcom...It wouldn't even connect to the port, it seems. According to the instructions, I typed:

microcom -D/dev/ttyUSB0

And is just hung there causing me to close xterm.

I;m outta ideas...I'll google some more with the hopes something will stick out.

Man, why did I hafta buy a house out in the country without broadband???why??? LOL

Posted by ShaneRay on July 18 2005,22:33

Well, I've been troubleshooting this in my spare time without any success.

If anyone should have any sugestions, by all means

As I said, works fine in the other distros I use (SuSE and Ubuntu)

Thanks

BTW, tried with wvdial as well...

Posted by SaidinUnleashed on July 18 2005,23:43

Did you try all the /dev/sttyX devices?

on some motherbords the external serial port is not 0 for some reason.

-J.P.

Posted by ShaneRay on July 22 2005,22:49

Yep, I've tried various nodes/ports. It certainly sees a serial port at ttyUSB0 as it "tries" to communicate. The others ilicits the "failed input/output error"---or something along thise lines.

However, I did notice for the 1st time last night (not sure how I missed it) that I get an error along the lines of, "failed to set write permissions /dev/ttyUSB0 read-only filesystem". So, I thought I'd try to chmod the node to different permissions but get the same error: read-only file system. I believe that's my problem...not sure how to fix it though.

Posted by cbagger01 on July 23 2005,03:31

Try this. Install the gnu-utils.dsl extension and then open an xterminal window and type:

sudo su
rm /dev/ttyUSB0
mknod /dev/ttyUSB0 c 188 0
exit

and see if it works.

Posted by ShaneRay on July 23 2005,17:20

Thanks for the help again cbagger.

I actually tried the mknod command yesterday, didn't work of course as I didn't know about that dsl extension....good stuff

Anyway, that cleared up the read-only file system problem. But, the same problems remain. DSL just won't communicate with the modem. I'm beginning to wonder if it's something to do with the kernal and/or the drivers for the usb-serial adapter. I thought I had read somewhere in my google travels that the 2.4 kernel had problems with it(sometimes)....not sure, though.

Anyway, think I'll give up on it for now. I have DSL working great on my old laptop; which was the main reason for getting DSL. Would love to be able to boot into it on my desktop, though. With "toram" my system feels like a pentium 5ghz...lol.

Thanks

Posted by cbagger01 on July 24 2005,03:30

If you want to check for linux compatibility information, check here:

< http://www.qbik.ch/usb/devices/ >