I have purchased a new notebook computer and it has all the features and ports that I require except an RS-232 serial port. I still have a need to test serial equipment in the field and to configure routers.

Can anybody suggest a RS-232 serial port adapter that is either USB or PCMCIA that is supported by the Linux 2.4 kernel?

Thank you.

Have a look in /usr/src/linux/Documentation/usb/usb-serial.txt

Thank you, Aussie. I reviewed the docs and decided on the Belkin F5U103 unit. Should arrive in a few days. I actually preferred the design of the Keyspan unit better, but the model number appears to have changed from the description in the docs as supported. Since the file & flush system is so specific I couldn't be sure of the support. The Belkin model was exactly as specified in the docs. Of course, with manufacturers today, that doesn't count for much either.

When I have tested the unit I will post here for an update.

Thanks!

I am currently having issues with usbserial converters... do you have any updates with the F5U103? Does anyone, or with any other USB-SERIAL converter/adapter? I currently have a couple of other USB-Serial converters:
Belkin F5U109 (http://catalog.belkin.com/IWCatProdu...oduct_Id=91042)
UC-232A USB Converter ( http://www.usb-port.com/uc232.html )
... and I have tried everyting suggested on http://www.linux-usb.org/ ... I am currently writing a write-up on all the steps I have taken, that hasn't worked and will post it on a a new thread later tonight....
I have my usb flashdrives and hard-drives working just fine, just no usbserial devices (gps, etc)

I have also tried this without any luck:

Quote:

If you only have USB @ your Laptop like me and no serial port, this will help you GPS getting started: type this london:~# insmod usbserial Using /lib/modules/2.4.18/kernel/drivers/usb/serial/usbserial.o usb.c: registered new driver serial usbserial.c: USB Serial support registered for Generic usbserial.c: USB Serial Driver core v1.4 london:~# insmod pl2303 Using /lib/modules/2.4.18/kernel/drivers/usb/serial/pl2303.o usbserial.c: USB Serial support registered for PL-2303 pl2303.c: Prolific PL2303 USB to serial adapter driver v0.9 Now plugin you GPS Device ... hub.c: USB new device connect on bus2/1, assigned device number 3 usbserial.c: PL-2303 converter detected usbserial.c: PL-2303 converter now attached to ttyUSB0 (or usb/tty/0 for devfs) Now your GPS Device is reachable via /dev/ttyUSB0 . It works fine. I configured GpsDrive with /dev/ttyUSB0 and it works ... -http://www.monolith81.de/gps.htm

At first I tried gpsd without any luck, so I tried cu and minicom... and got the same results... no serial port on either /dev/ttyUSB0, /dev/ttyUSB1 ... /dev/usb/ttyUSB0...etc.. always getting the error message that the device does not exist... nothing in my dmesg that states any errors concering USB... i have rm'd the ttyUSB* and used /sbin/modprobe usbserial ... no errors, only nothing works

... thinking of doing pcmcia serial, but would like to know if anyone has had any success with usbserial... anyway I will post a more detailed and logical writeup later this evening regarding my issues.

The Belkin unit worked great for me. I am not sure though about the kernel version. I had many devices that did not want to work correctly with 2.4.18 kernel. I upgraded my notebook to 2.4.19 kernel. Every device I have works correctly with 2.4.19 kernel. I confirmed the model number of my USB serial device, F5U103. Your unit may require a kernel update. The latest current stable is 2.4.20.

Thanks for the update!... I will update my kernel this evening (don't recall offhand which version it is at)... though I just found another usbserial device on the web:
the Keyspan "High Speed" USB Serial Adapter
http://keyspan.com:16080/products/usb/USA19W/
which has linux support in the kernel (2.4.1+)
http://www.keyspan.com/support/linux/
Keyspan Drivers Mini-Howto Page
http://www.keyspan.com/support/linux/LinuxReadMe.html
I recall seeing these at Fry's, but don't recall seeing the F5U103 at any local retailer recently... so I will be sure to add one of these to my collection this evening... and then try again! I will post any updates here as well Thanks again!

I didn't think about posting any details regarding the Belkin serial adapter before. After the last post, it might provide you with some assistance.

I load the Belkin module from the rc.local script in Slackware.

modprobe belkin_sa

The device uses /dev/ttyUSB0 to function. If you deleted this and you need to recreate it then use

mknod /dev/ttyUSB0 c 188 0

Character device on major 188, minor 0

Using the 2.4.19 kernel the only USB or firewire device I have had to force has been my Epson Scanner. It was a newer model than what was listed as supported so I was expecting that. But if you think you would like to test a device using an existing driver, many modules allow you to force the detection by providing the ID codes when the module is loaded. For example, from my Epson Perfection 1660 Photo scanner;

modprobe scanner vendor=0x04b8 product=0x011e

Notice the numbers are in hex notation. To determine the ID's for your device, use "dmesg" directly after attaching the USB device. I think some of the low level USB hub drivers have to be loaded to enable the USB hub and then to report the device. The newer Belkin unit may work if forced in this manner. After detection, remove the device, unload the module if loaded, reload with the parameters, and then reattach the device. The module should then pick it up. The same procedure may also work for the Keyspan unit. If the module complains about the parameters or ignores them, then review the source code (header and source files) for the module and see if the writer made any suggestions. If no provision is provided to force it, and if you can locate the ID's in the source, then hack it by adding your ID's codes and recompiling.

Unfortunately, I didn't know this could even be done back when I was searching for a device. My new notebook forced me to learn a lot about modules, USB and Firewire. Of course, it is always better to purchase a unit that is listed as supported to begin with. But today, the hardware changes so quick, how can software manage to keep up? If a product is well supported and tested then it has probably been discountinued.

If I recall correctly though, 2.4.18 supported the Belkin F5U103 just fine. I had to upgrade for support of Firewire devices. So you may desire to attempt the Belkin driver on your F5U109 device.

Good luck.

Thanks again Excalibur as you well know from the missing tux thread that all things are now going a lot better... I am now using 2.4.20 and the keyspan is working great (I haven't tried my other converters yet, but I will, just it isn't a big deal since one of them is working right now)...

Currently an issue with the usbserial is that I connect my gps (using NMEA/4800) and to test out to make sure my system can see it correctly I test it with cu (cu -l /dev/ttyUSB0 -s 4800) and I can see the correct NMEA sentences coming through just great... though I can't seem to terminate cu with ~. as the man pages dictate and have to switch to another VT login and kill the process... :/ (if you know an answer to this, that would be great!) [I even tried esc, esc, ~, ~, . and a ton of CTRL combinations]

... even though that I can now apparently communicate successfully with the usbserial device it seems that gpsd for some reason or another does not like it using gpsd -p /dev/ttyUSB0 and then ps -A | grep "gpsd" I can see that gpsd isn't using /dev/ttyUSB0 as it probably should since it has a question mark by it rather than the device it is using... also when using telnet localhost 2947 and typing R, I don't see the sentences come across but rather toggle a single like =1 or =0 ... and when I bring up gpsdrive it freezes the entire system... and I have to power down and power up again ... if you or anyone can help me with this that would be wonderful, but regardless I will find out what is going on since this is not acceptable if I want to use gpsdrive successfully.

quick update:

no idea what occurred over the 40 plus kernel recompiles... but now this is working like a dream... using my gps over usbserial with gpsd and gpsdrive and all works super great... i am not getting the weird lockups when starting gpsdrive as I previously was... <twilight zone music here>

Setup: successfully running slackware 8.1 using kernel 2.4.20 and the USA-19QW keyspan usb-serial converter using the kernel drivers instead of modules. GPS: Garmin eTrex Legend at NMEA/4800. (I don't use the Garmin protocol since it isn't compatible with a few other pieces of software I use this GPS on other platforms)