Serial port = lack of hair!
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Serial port = lack of hair!
28-09-2010 7:22 PM
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I reboot into Ubuntu and download cutemon (I liked the name) and gtkterm, Ubuntu finds the device as a Prolific PL-2303 (though I believe it's the 2303X) and assigns it to ttyUSB0 so in cutemon/gtkterm/putty I connect to ttyUSB0 and the result is either garbled nonsense (gtkterm) or 0x00 (cutemon). I'm pulling my hair out in frustration, I want to get my Cisco 857w working but DCHP isn't on so it won't assign an IP address and forcing it with the gateway at 10.10.10.1 or 10.0.0.1 or 192.168.0.1 or 192.168.10.1 doesn't let me log in to the router (assuming of course that HTTPD is on).
So, can anyone think of a reason why I'd get 0x00 from cutemon, putty shows nothing (or maybe a lot of pppppppp's) and I'm basically unable to connect to the router via the console cable?
Re: Serial port = lack of hair!
28-09-2010 7:26 PM
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Re: Serial port = lack of hair!
28-09-2010 7:31 PM
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Re: Serial port = lack of hair!
29-09-2010 9:31 AM
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Connect your RS232 terminal adaptor.
Run your RS232 terminal emulator program and run it in VT100 mode if possible.
Type a few characters, and see if anything is echoed to the screen.
Connect the RS232 "TX" to "RX" together (usually pins 2 and 3) - easy to do with a metal screwdriver !.
Type some more characters and see if the echoed characters have changed.
This test will check if you can at least transmit something, by effectively listening to your own output.
If that fails then you might not be transmitting because of hardware handshaking.
This time wire the RTS and CTS lines together (pins depend on connector type ! - so you need your handbook)
Repeat the previous TX/RX test.
Hopefully now your TX has been unblocked.
You need to get to a point where you are getting exactly one correct echo for every character typed - BEFORE connecting the Cisco
Good luck
Re: Serial port = lack of hair!
29-09-2010 10:25 AM
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Re: Serial port = lack of hair!
29-09-2010 11:02 AM
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I used to use "HyperTerminal" for this sort of RS232 work.
You should be able to download the latest free 30 day trial version, from a simple google.
I don't know about Windows-7, but Windows-XP used to come with an ancient version of "HyperTerminal" (start->Accessories->Communications->), I seem to remember form years ago that this version was not that great (but I was doing major RS232 debugging) - but if it is already on your machine, then it might be enough to get you going.
Re: Serial port = lack of hair!
29-09-2010 12:51 PM
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With nothing plugged in I get no response, if I plug in the console cable with the Cisco turned off, no response, if I turn on the Cisco I get \0x00 so something is being fed to the device? Well, there is lot's of traffic now but it's all jibberish. It's not as though I have any other serial device to check if it's the serial cable either.
So, there does seem to be traffic coming from my router but somewhere along the line it's being corrupted, could it be the serial side is miswired?
/edit - in a terminal window I typed cp /dev/ttyUSB0 /dev/tty which outputs the result of ttyUSB0 apparently, and in a new terminal window typed echo test_message > /dev/ttyUSB0 which *should* have displayed it on terminal window 1, but that remained blank.
Re: Serial port = lack of hair!
29-09-2010 1:56 PM
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Check the settings for handshaking settings as well.
Do you have an old serial modem lying around that would be best to test it on?
Re: Serial port = lack of hair!
29-09-2010 2:02 PM
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Re: Serial port = lack of hair!
29-09-2010 8:02 PM
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I've installed the Win7 drivers but not the latest, the latest give me a silly Cannot start 10 error so I have to use 1.20 rather than 1.30, Linux though the drivers are built into the kernel now.
/edit - I've ordered a Belkin USB to Serial which uses the same chipset (joy!) but is a "branded" product, and got a refund on the faulty one. It was either that or make my own serial cable and plug it into the headers on my motherboard which would have resulted in a whole new "oh, I broke my motherboard..." thread
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