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Old 09-21-2004, 06:14 PM   #1
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Unhappy ttyS0 is half-dead!?


I have an half-dead ttyS0...

I have been using ttyS0 to talk to my devices(DSP, RF com cards,...) at different baud rates....
Each time, I opened minicom set my baudrate, and turn my device on... then a log message would appear on minicom or even a friendly config menu from my RF card ...
Anyway, till last week my life was peacefull...
Today this is what happen: when I go through the same steps I get an online from minicom but nothing on the screen, i.e. no damn log message or menu... I've verified the baudrate, the terminal emulation, even checked the permissions, logged myself in root and did a chmod 0777 just to be sure nothing's on my way to talk to my devices...
But nothing... o_O
One weird thing is that it looks like I can still send through ttyS0 cause when I hit 'esc' in the menu for my RF device the leds on the device turned red which means it got an reboot request...
My last option was to test using a db9 connector and soldering pin 3 and 2 together, turn the echo on and see what's going on...results: No echo!

So my question is: Is there a way this could be due to a soft pb or is my RX on ttyS0 just died????

Last edited by TsaLLgood; 09-22-2004 at 10:55 AM.
Old 09-21-2004, 06:32 PM   #2
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Here is a complete schematic of a 9 pin loop back plug.

Just jumpering the TX/ RX may not work depending how the com port is configured.

Its possible that you have a hardware problem. Is this a store bought cable?
Old 09-22-2004, 11:18 AM   #3
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Registered: Sep 2004
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Hi Michael,

would appreciate any help I can get here.....

actually no it's a serial cable I made myself...

It would be the problem, but I've modified a com connector so that pin 2 and 3 are connected together and connected it to the com1 port directly on the PC tower and no echo in minicom...

One thing is, this PC has not been turned off for like a year which I don't agree with doing so... thus Last week I decided to reboot the tower... and since then, I'v got this pb.. that's why I was thinking of a config file pb...


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