How connect Mp mode 25pin?

[Silvea]

When connected with 25 pin, pressing Ctrl+B  in the picture above will not respond.

Is it a cable problem?

[Steven Schweda]

> When connected with 25 pin, [...]

   When _what_ is connected to _what_, exactly?

> Is it a cable problem?

   I don't know.  I don't know what you connected to what with what.

   Does your Windows (laptop?) computer have a (9-pin) serial port, or
are you using that USB/Serial adapter to add one?  What is connected to
the USB port on the back of that (unspecified) HP server?  What is that
server, an rx2600, or what?

   If you're trying to talk to the iLO/MP console port on the server,
then you should be connecting a terminal/emulator serial port to the
"CONSOLE / REMOTE / UPS" connector on that server, through whatever
adapter(s) (9-pin/25-pin, null-modem?) you might need to connect the
hardware correctly.  (9600b/s, 8 data bits, 1 stop bit, no parity, I
believe.)

   On these servers, the 25-pin connector actually presents three serial
ports (CONSOLE, REMOTE, and UPS), and there's a three-way splitter
cable to provide access to all three, but the CONSOLE port appears at
the standard pins on the 25-pin connector, so a normal 25-pin cable
should connect you to the CONSOLE port.  The HP part number for the
splitter cable is A6144-63001.  You may not need the splitter, but a Web
search for that part number should find many things.

[Bill Hassell]

One of the most common failures with RS-232 connections is pin 2 & 3 swaps. While there are very specifc standards for the transmit and receive pins, they were defined 50 years ago. No USB, no 9 pin plugs, just modems and computers. While a lot of research might be able to track down exactly the right cable wiring, just purchase a 9 pin null-modem adapter. It is nothing more than a swap of pins 2 & 3. If you don't see a response to CTRL-B, insert the null-modem adapter and try again. Something like this:

This adapter should be a part of any serial connection kit.
Less than $10 USD at Amazon.

[Silvea]

Is the cable in the picture above different from the 9-pin null modem adapter?

[Patrick Wallek]

What model server are you trying to connect to?

[Steven Schweda]

> Is the cable in the picture above different from the 9-pin null modem
> adapter?

   Are you serious?  Using his X-ray vision, perhaps Superman could
answer that question, _if_ he could see the actual cable.  Given a
_picture_ of a cable, even Superman would be helpless.

> [...] It is nothing more than a swap of pins 2 & 3. [...]

   It _is_ more, but some of the "more" may not matter much in this
application.

      https://en.wikipedia.org/wiki/Null_modem

[Bill Hassell · Accepted solution]

As Steven mentioned, there is no way to look at a picture and determine the wiring. If it was packaged as a null mode cable, then it would probably accomplish the goal of swapping pins 2 and 3. I would just try it to see if it works. There are other pins that may be active but without detailed design docs for this mystery server and all the cables and adapters, all you can do is experiment. Other issues might be that the MP port was set to some other baud rate or the MP port is locked up and needs to be reset.

Do you have access to the MP using the console LAN port on this mystery server?

If you have a breakout box and a meter or a scope, you may be able to figure out what's happening.

[PDP-Fan]

Is this an RX server? The MP port has three different serial ports on the same 25pin connector. Not a standard pinout at all.

- Modem (Remote)
- Console (this is what you need)
- UPS (communication to an UPS system)

Normally you will use an adapter cable from 25pin connector to 3 connectors 9pin. I have never used the MP port without that adapter.

[Steven Schweda]

> [...] The MP port has three different serial ports on the same 25pin
> connector. Not a standard pinout at all.

   Not entirely true.  Did you read the first reply, above?

> Normally you will use an adapter cable from 25pin connector to 3
> connectors 9pin. [...]

   Normally, you'd _need_ such an adapter, _if_ you wanted to use the
REMOTE or UPS ports, not if all you wanted was the CONSOLE port.

> I have never used the MP port without that adapter.

   I have never used the iLO/MP port (on my rx2600 systems) _with_ that
adapter, because I didn't need it.