usb => serial port converter

[Lee]

What's everybody using for a usb => serial port converter?

I got a new network switch and .. OhNoes!! how to I talk to the darn thing???

I went looking thru cabinets and came up with a keyspan usb -> serial
dongle; a quick search found the site with driver downloads, but they
all were for Windows or MacOS. I tried plugging the dongle into my
debian laptop but it didn't recognize it :(

So... what are people using to talk to serial devices now that PCs
don't come with serial ports anymore?

And what program are you using to talk to something over the serial
link? pterm or something else?

I still have a Windows machine, so install the drivers, configure
putty to talk to COM4 & I'm good to go. But I'm trying to get *away*
from Windows. How do I talk to my switch over the serial port?

Thanks,
Lee

[f***@protonmail.com]

Post by Lee
What's everybody using for a usb => serial port converter?
I got a new network switch and .. OhNoes!! how to I talk to the darn thing???
I went looking thru cabinets and came up with a keyspan usb -> serial
dongle; a quick search found the site with driver downloads, but they
all were for Windows or MacOS. I tried plugging the dongle into my
debian laptop but it didn't recognize it :(
So... what are people using to talk to serial devices now that PCs
don't come with serial ports anymore?
And what program are you using to talk to something over the serial
link? pterm or something else?
I still have a Windows machine, so install the drivers, configure
putty to talk to COM4 & I'm good to go. But I'm trying to get *away*
from Windows. How do I talk to my switch over the serial port?
Thanks,
Lee

i've used this for many years

Bus 001 Device 006: ID 0403:6001 Future Technology Devices International, Ltd FT232 Serial (UART) IC
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x0403 Future Technology Devices International, Ltd
idProduct 0x6001 FT232 Serial (UART) IC
bcdDevice 6.00
iManufacturer 1 FTDI
iProduct 2 UC232R
iSerial 3 FTF588Y9

[gene heskett]

Post by Lee
What's everybody using for a usb => serial port converter?
I got a new network switch and .. OhNoes!! how to I talk to the darn thing???
I went looking thru cabinets and came up with a keyspan usb -> serial
dongle; a quick search found the site with driver downloads, but they
all were for Windows or MacOS. I tried plugging the dongle into my
debian laptop but it didn't recognize it :(
So... what are people using to talk to serial devices now that PCs
don't come with serial ports anymore?
And what program are you using to talk to something over the serial
link? pterm or something else?
I still have a Windows machine, so install the drivers, configure
putty to talk to COM4 & I'm good to go. But I'm trying to get *away*
from Windows. How do I talk to my switch over the serial port?

See if you can find a usb-232 from FDTI. And keep looking if you see a
Prolific, its not very good.

Post by Lee
Thanks,
Lee
.

Cheers, Gene Heskett, CET.

[Andy Smith]

Hi,

I tried plugging the dongle into my debian laptop but it didn't
recognize it :(

In my experience USB serial gadgets on Linux tend to just work or
will never work. The default Debian kernels do have USB serial
converter support enabled and all the drivers as modules. You'll
probably find it a better use of your time to just buy one that is
known to work, as they are quite cheap.

So... what are people using to talk to serial devices now that PCs
don't come with serial ports anymore?

Here are some notes from FreeBSD, which is a bit pickier than Linux
on this, so should be conservative advice:

https://wiki.freebsd.org/USB/Peripherals/Serial

And what program are you using to talk to something over the serial
link? pterm or something else?

I use either minicom or GNU Screen. You'll need to know the baud
rate that the device expects, though you can just try a few common
ones and see what works. e.g.

# screen /dev/ttyUSB0 115200

Thanks,
Andy

[Lee]

Post by Andy Smith
Hi,

I tried plugging the dongle into my debian laptop but it didn't
recognize it :(

In my experience USB serial gadgets on Linux tend to just work or
will never work.

It worked this time!
Other than plugging it into a windows machine that had the proper
drivers first, I don't know what changed.

Post by Andy Smith

And what program are you using to talk to something over the serial
link? pterm or something else?

I use either minicom or GNU Screen. You'll need to know the baud
rate that the device expects, though you can just try a few common
ones and see what works. e.g.
# screen /dev/ttyUSB0 115200

Great! I had to add myself to the dialout group to be able to talk to
the device, but
screen /dev/ttyUSB0 38400
works.

Thanks
Lee

[Jeffrey Walton]

Post by Lee

Post by Andy Smith

I tried plugging the dongle into my debian laptop but it didn't
recognize it :(

In my experience USB serial gadgets on Linux tend to just work or
will never work.

It worked this time!
Other than plugging it into a windows machine that had the proper
drivers first, I don't know what changed.

Post by Andy Smith

And what program are you using to talk to something over the serial
link? pterm or something else?

I use either minicom or GNU Screen. You'll need to know the baud
rate that the device expects, though you can just try a few common
ones and see what works. e.g.
# screen /dev/ttyUSB0 115200

Great! I had to add myself to the dialout group to be able to talk to
the device, but
screen /dev/ttyUSB0 38400
works.

You should also add TIOCEXCL on the file descriptor to ensure
exclusive access to the device. Otherwise, other programs will try to
open the modem and probe it by sending commands to it. It will screw
up your reads on the fd.

/* NetworkManager and ModemManager will try to open our device */
/* on occasion. Set TIOCEXCL to ensure we get exclusive access */
if (ioctl(fd, TIOCEXCL, NULL) == -1) {
log_warn("Failed to set TIOCEXCL on device: %s\n", strerror(errno));
}

Jeff

[Max Nikulin]

Post by Lee

Post by Andy Smith
In my experience USB serial gadgets on Linux tend to just work or
will never work.

It worked this time!
Other than plugging it into a windows machine that had the proper
drivers first, I don't know what changed.

Some devices may advertise them as mass storage drives at first to
autorun windows drivers installer. I would not expect it from a cheap
serial port adapter though. See the usb-modeswitch package to change
exposed USB interface from command line.

Post by Lee
Great! I had to add myself to the dialout group to be able to talk to
the device, but
screen /dev/ttyUSB0 38400
works.

systemd-logind may grant access to the currently active user. Search for
"uaccess" in /usr/lib/udev/rules.d/

<https://github.com/systemd/systemd/issues/4288>
"Document the uaccess mechanism / dynamic device permissions"

<https://enotty.pipebreaker.pl/2012/05/23/linux-automatic-user-acl-management>
Tomasz Torcz. Linux automatic user ACL management

[t***@tuxteam.de]

Post by Lee
What's everybody using for a usb => serial port converter?
I got a new network switch and .. OhNoes!! how to I talk to the darn thing???

Most of them work with Linux anyway (some of them with some
limitations). Stick it in and look at the logs.

Usually there is a device /dev/ttyUSBxxx. That one is your
friend.

Post by Lee
I went looking thru cabinets and came up with a keyspan usb -> serial
dongle; a quick search found the site with driver downloads, but they
all were for Windows or MacOS.

Ah, the privileges of proprietary software :-) You not only get
to pay, but you get to put more dubious software into your box.

Post by Lee
I tried plugging the dongle into my
debian laptop but it didn't recognize it :(

What does "lsusb" say? What does "dmesg | tail" say shortly after you
inserted your dongle?

Cheers

[Paul Duncan]

Hi Lee,

Its very much "horses for courses".

If all you want to do is talk to network switch console ports, there are
cheap cables from Amazon that will do that.

If you *only* want a general purpose RS-232 StarTech and TrendNet should
just work.

If you want to be able to do other things like RS-422 and RS-485, I would
recommend a Moxa uPort 1150. Be aware that you will have to install the
Moxa driver to use this - its not generally included with the kernel.

Cheers,

Paul.

Post by Lee
What's everybody using for a usb => serial port converter?
I got a new network switch and .. OhNoes!! how to I talk to the darn thing???
I went looking thru cabinets and came up with a keyspan usb -> serial
dongle; a quick search found the site with driver downloads, but they
all were for Windows or MacOS. I tried plugging the dongle into my
debian laptop but it didn't recognize it :(
So... what are people using to talk to serial devices now that PCs
don't come with serial ports anymore?
And what program are you using to talk to something over the serial
link? pterm or something else?
I still have a Windows machine, so install the drivers, configure
putty to talk to COM4 & I'm good to go. But I'm trying to get *away*
from Windows. How do I talk to my switch over the serial port?
Thanks,
Lee

--
*Paul Duncan*

Lead Marine Technician, RV Falkor(too)

SCHMIDT OCEAN INSTITUTE

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