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Re: Serial Connection

On 28/03/11 11:46, Stephen Powell wrote:
> On Sun, 27 Mar 2011 16:27:08 -0400 (EDT), Stan Hoeppner wrote:
>> For attaching a terminal all you need to connect are pins 2, 3, and 7 on
>> a DB25, or 2, 3, and 5 on a DB9.  Reverse 2,3 on one end of each cable
>> to get your x-over.  All the other pins are for modems only and are not
>> used for terminal connections.  Serial printers only need 2, 3, 7 as well.
> That would be transmit data (TD), receive data (RD), and signal ground (SG),
> respectively.  That is the minimum.  But it may not be sufficient.
> If the terminal is set up for hardware flow control, for example, it
> won't be sufficient.  Besides, the OP wants to cross-cable two servers
> together, it seems, and use a minicom session on one to open a terminal session
> on the other.  minicom was written for use with a modem and probably
> expects more of these lines to be functional than just TD, RD, and SG.
> The devil is in the details.  If he uses a full cross-over cable, as
> outlined in
>    http://en.wikipedia.org/wiki/File:D9_Null_Modem_Wiring.png
> (or a standard serial cable with a similarly wired null modem), it should
> work with any DTE-to-DTE connection.

If using hardware control then yes, three wires is not enough (you'll
get garbage), if using software control he should have no problems.
I use that set up frequently without problems

Specifically:- minicom both ends, software control on. (It'll also work
for laplink under DOS).

For a quick solution when a proper cable is not on hand:-
Strip a centimetre or two of insulation off both ends of three lengths
of wire, using a nail or toothpick as a former make a wire wrap/coil,
cover the wirewrap/coil in tape and carefully slide it off the former
onto the serial pin. Works fine - I also use the same setups for quick
and dirty serial port logging connections. Haven't tried it for printers.

Currently using exactly that setup to monitor an old SGI Octane on the
workbench now.


> A: Yes.
> >Q: Are you sure?
> >>A: Because it reverses the logical flow of conversation.
> >>>Q: Why is top posting frowned upon?

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