Hi everybody,
This is my first post to this list (but some of the names of people here are familiar from other lists etc)
I am not exactly sure what was meant by the original question:
Do you want
1) to connect a serial terminal to you linux box that (say) has USB ports but not serial ports. Or
2) connect a USB cable between two linux boxes, with one running a terminal program. (i don't know why you'd want this but hey.
for 1. its easy. just buy a usb to serial converter like the DSE XH6381. i have three of them and they are great. they use a FTDI chip which has quality drivers for all major operating systems.
for mine, i used the ftdi utility to reprogram the onboard eeprom so that it has a standard VID/PID and works without specially configuring the drivers, but that was a while ago and shouldn't be needed anymore.
for 2. its also possible but you'd probably need to write your own driver emulating a tty interface, and make a special cable which would need some smarts/electronics in it. USB is a one-way interface in that one end is the HOST and the other is the DEVICE. You can't make a null modem cable for USB.
TO CHRIS:
If you were referring to the XH6381 in your post, then sorry you are wrong -- its got electronics inside. for my first one before the ftdi eeprom utilit was available i cracked it open and de-soldered the eeprom to reprogram it -- there is actually a small pcb in there. Also, i have never heard of anyone blowing anything up if they use a proper adapter like the XH6381. BUT if you do connect just the wires without a proper electronic adaptor you will definitely damage your USB controller on your motherboard (serial runs at +/- 12V and USB runs at 3.3V and 5V)
USB is very very different to serial (specifically RS232 the 9-pin or 25-pin ports on the back of your box). The only common part is that they both transmit data serially (i.e bit after bit after bit).
USB operates on low voltage differential signalling -- RS232 on high voltage single-ended signaling. USB has a protocol stack -- RS232 has nothing you just send that data and hope for the best. USB needs a special chip and special software and special drivers on the PC -- RS232 needs nothing special.
ABOUT SETTING UP A CONSOLE OVER USB_SERIAL:
I am not sure about getting the console during boot (its probably possible but probably not worth the effort...) but getting a console once its booted is trivial. the usb-serial port will come up as just another serial port (/dev/tty*) and can be configured as a console but making a getty process for the port. read the getty man page.
I hope this answers some ppls questions. Regards, hugo
On 21/05/2004, at 12:02 PM, Chris Day wrote:
-----Original Message----- From: Bart Hanson [SMTP:[EMAIL PROTECTED] Sent: Thursday, May 20, 2004 11:13 PM To: CLUG Subject: Re: console via usb
On 18/05/2004, at 8:16 PM, Vik Olliver wrote:
On Tue, 2004-05-18 at 18:52, Paul William wrote:Hey all,
Anyone know if you can get a 'Serial' Console using usb instead of a
serial port? I don't really care about having a console at boot up but
it would be a bonus.
The only documentation I can find is about using the serial port.
USB Just doesn't work that way.
I have a USB -> Serial adaptor that doesn't appear to have any electronics or smarts, just a redirection of the wires. I too would like to know why USB can not function as a serial port controller. Anyone ?
This is my first question to the list, I hope I can help someone else
sometime although I'm a Unix "baby".
Real briefly - serial is a fairly dumb interface - USB is a smart interface
- the 2 are 100% NOT compatible.
The adapter you have is commonly used with a mouse or similar peripheral
that has a smart controller chip in it that is designed to handle USB or
Serial. Be warned that it is possible to damage devices by incorrectly
using the adapter you have - its designed for a specific purpose and
converting USB to Serial, in the true sense, is not that purpose. This is
the reason why DSE does not and will not sell such an adapter - people will
blow things up.
Regards, Chris...
