[ltp] IBM 600E, RH9, minicom problem

Bill Voight linux-thinkpad@linux-thinkpad.org
Sat, 28 Feb 2004 10:19:31 -0500


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Heiko,

Thanks for the info.  I'll try to get my hands on a scope.  FYI, a U2 is 
a Sun Microsystems Ultra Enterprise 2- an older Sparc 2 box.

Heiko Rosemann wrote:

Heiko Rosemann wrote:

>Hi,
>
>On Fri, 27 Feb 2004, Bill Voight wrote:
>
>  
>
>>Sports fans,
>>
>>IBM 600E, RH9, minicom serial port  Setup- /dev/ttyS0 9600 8N1, Hardware
>>flow control, no Software Flow Control
>>
>>I'm using settings identical to those I've been using on several other
>>RH boxes to connect to the A serial port of some U2's.  I am using a
>>known good null modem cable and gender bender to connect.  Works fine on
>>the desktops, no dice on the IBM 600e.  I've run the diags from the
>>600E's bios- they show everything's OK.  Have had no luck with docs- I
>>haven't found anything indicating there's anything different about the
>>serial port on a 600E.  Setserial output from both is listed below- it's
>>identical.  Anybody got any ideas?
>>    
>>
>
>I recall there have been a few problems with laptops who do not deliver the
>standard +15V/-15V RS232-signals, but lower voltages (+7V/-7V is a number I
>seem to recall) So if you have some access to a scope, it might be worth
>measuring the voltages on the port pins. Most serial devices work with
>signals that low, but some refuse.
>
>Another possibility: Quite a few serial devices draw power from the port
>(more specifically the handshake lines) I don't know what a "U2" is, so I'm
>just guessing here, but it could be that it is exceeding the RS232 specs in
>terms of current draw, so it won't work with the maybe more spec-conformant
>laptop port.
>
>Do you have any other device to test the port with? What happens if you just
>connect RXD and TXD (pins 2 and 3 on the 9pin-connector) and try
>transmitting without any flow control?
>
>HTH, Heiko
>  
>

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Heiko,<br>
<br>
Thanks for the info.&nbsp; I'll try to get my hands on a scope.&nbsp; FYI, a U2
is a Sun Microsystems Ultra Enterprise 2- an older Sparc 2 box.<br>
<br>
Heiko Rosemann wrote:<br>
<br>
Heiko Rosemann wrote:<br>
<blockquote type="cite"
 cite="midPine.LNX.4.58.0402281437270.1331@x30.rosemann">
  <pre wrap="">Hi,

On Fri, 27 Feb 2004, Bill Voight wrote:

  </pre>
  <blockquote type="cite">
    <pre wrap="">Sports fans,

IBM 600E, RH9, minicom serial port  Setup- /dev/ttyS0 9600 8N1, Hardware
flow control, no Software Flow Control

I'm using settings identical to those I've been using on several other
RH boxes to connect to the A serial port of some U2's.  I am using a
known good null modem cable and gender bender to connect.  Works fine on
the desktops, no dice on the IBM 600e.  I've run the diags from the
600E's bios- they show everything's OK.  Have had no luck with docs- I
haven't found anything indicating there's anything different about the
serial port on a 600E.  Setserial output from both is listed below- it's
identical.  Anybody got any ideas?
    </pre>
  </blockquote>
  <pre wrap=""><!---->
I recall there have been a few problems with laptops who do not deliver the
standard +15V/-15V RS232-signals, but lower voltages (+7V/-7V is a number I
seem to recall) So if you have some access to a scope, it might be worth
measuring the voltages on the port pins. Most serial devices work with
signals that low, but some refuse.

Another possibility: Quite a few serial devices draw power from the port
(more specifically the handshake lines) I don't know what a "U2" is, so I'm
just guessing here, but it could be that it is exceeding the RS232 specs in
terms of current draw, so it won't work with the maybe more spec-conformant
laptop port.

Do you have any other device to test the port with? What happens if you just
connect RXD and TXD (pins 2 and 3 on the 9pin-connector) and try
transmitting without any flow control?

HTH, Heiko
  </pre>
</blockquote>
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