About MUX 8-port and Printer

[Thanasis_3]

Hi,
I have a 8port mux (RJ45 10-pin)(A6748-60001) and I want to install a dot matrix printer(OKI Microline) on it. I also buy a RJ45 to DB25 converter (J3830-60010) from HP. I've connected the printer, I've installed it as a "dumb" pirnter on port "a1" and when I'm trying to print something nothing happens. After some seconds the print job is being lost!
I also tried to do this: cat /etc/hosts > /dev/tty2a1 and
nothing happens!
I've checked the printer and it is working perfectly.
Nothing else is connected to the other ports of mux.

[Zigor Buruaga]

Hi,

Could you please post the output of "netstat -fn" and "lpstat -t".

Kind regards,
Zigor

[melvyn burnard]

sounds to me like you have a cable htat is eihter wired up wrong, or boken. try putting a dumb terminal on it and see what appears when you do hte cat command.
Also try putting a breakout box onto the db25 side and see what signals you get/dont get

[Zigor Buruaga]

Oppss ...
Sorry, is "ioscan -fn", not "netstat -fn".

Doing three things at the time ... ;-)

Kind regards,
Zigor

[Thanasis_3]

Well.. There is nothing wrong with the cables. The cable from mux connects directly to the printer without any intermediate cables.
The result of ioscan is attached with this message (fortunately, I had it with me). I can't tell you about the lpstat -t command cause the Server is not in my office but far away from here.

I aslo tried to use a different mux port and a different printer but the same happened.



Thank you in advance.

[Zigor Buruaga]

Hi,

"ioscan" output looks fine to me.

The output of "lpstat -t" is still needed to know if the scheduler is running, if the message was sended or not to the printer, or remains in the spool.

Kind regards,
Zigor

[Thanasis_3]

Hello again,

As far as I can remember, the scheduler (and the spooler,too) was running normally.
By typing "lpstat" I was able to see the print job .. but after 10 seconds it was gone!

I'm afraid that I can't give you more info today, cause as I've said the Server is not in my office.
I was thinking.. if I could use a terminal on this port to see what it will print...

[Darren Prior]

Hi,

The RJ45-DB25 converter has a female DB25 connector, printer serial ports are also female, so it isn't possible to just use this converter without any other cables or adapters.. The adaptor converts from one connector type to another, you'll then need a suitable cable between the converter and the printer. If you've put a gender changer between the converter and the printer then the transmit and receive lines are fine, but the handshaking is different.

Here's more info on cabling for these muxes: http://docs.hp.com/hpux/onlinedocs/5966-8703/5966-8703.html

Compare the pinouts for the modular printer cable with the RJ45-DB25 converter pinout.

regards,

Darren

[Thanasis_3]

Hello!

Thank you for the reply and excuse me for this mistake :) . I'm using a gender adaptor for this connectivity, but I don't think that this adaptor changes the wiring method. That's why I said that the cable is directly connected to the printer.

So, you're telling me that, except the adaptors (RJ45-DB25) I bought, I need special cables for the adaptor_to_printer connection??

I'm sending a snapshot of the gender adaptor I'm using (to be more spesific)

[Darren Prior]

Hi,

Consider yourself excused ;-)
I would have to assume that the gender changer is a straight through connection. I've spoken to many people who have used modems with cables connected to the RJ45-DB25, but haven't spoken to people who have connected their printers in this way. What I'm trying to say in a roundabout fashion(!) is that I'd suggest you aim for a cable that gives you the same connectivity as the terminal/printer cable in the document I mentioned earlier, as I'm not sure of the importance of the handshaking with your printer.

regards,

Darren

[Thanasis_3]

Hi again!

Thank you for the reply (again! :) )
I'll check it out and I'll send u a feedback when I'm done with this (...hopefuly!!)

See you on monday ...

[Manish Bharadwaj]

Hi

I think Darren is pointing you in right direction. At this stage forget about lpscheduler, first you should get printer to print. The trick is to get right cable. If possible try to connect it with straight gender bender if it fails try with cross gender bender. If you can solder the cable I will try to Short pin 4 and 5 and also ping 6 , 8 and 20 at printer end.

[Bill Hassell · Accepted solution]

The problem is DEFINITELY wiring. The RJ-45 connector was never designed to be used for RS-232. In fact, EIA RS-232C (the spec for serial communication) ONLY defines the full DB-25 style connector--do DB-9 connectors are non-standard. However, IBM defined the DB-9 pinouts with the very first PCs and luckily, all the manufacturers for cables and connectors made the DB-9 wiring a de facto standard.

Unfortunately, there is no standard for RJ-45 wiring used with serial devices. (even the RJ-45 used in LAN connections 'borrowed' the design from the phone industry) While the connector is very useful because of it's size, I have found at least 5 different versions of RJ-45 wiring in cables and adapters. And NONE of them are compatible with the HP MUX panel. The manual goes into great detail defining the pinouts but leaves out one important detail: the J3830-60010 cable is not defined as a modem (straight-thru) or a printer (crossover) cable. The difference is the number one reason why serial connections don't work the first time.

Run down to the local PC shop and get a DB-25 null-modem adapter. That way you can try either wiring method by simply inserting the crossover adapter.

If this doesn't get the printer working, time to get down to bits and bytes. Replace the printer with a terminal (I call it a glass printer). You may have problems in your printer with requirements for CarrierDetect and/or DataSetReady. Use the terminal to see that data is getting to the device. Don't use the spooler to test the port (too much software in the way). Use the EISA/PCI MUX diagnostic: emux_diag to set the baud rate and generate a test pattern. If the pattern gets through to the terminal but not the printer, the printer likely needs a control signal (CD or DSR) asserted true before it will print. This may require building a custom cable (oe easier: a DB25 adapter)

[Thanasis_3]

Well..

I compared the DB25 of the adaptor and the DB25 of the printer and I realize this: The CTS is on the 22 pin of the adaptor contrary to the printer's port in which the SSD is on the 11 pin.
So, I thought that I had to make a cable redirecting the 22pin of the adaptor to 11pin of the printer so that the handshaking would work.
(the DSR,SG,TS,RD are ok)

_BUT_

Until now, my customer was using an MPE system with these printers. The serial cables have only 3 wires (2,3 and 7).
I want to use the same cables and printers with the new machine (HP-UX), SO I don't have to make any changes to the cable, haven't I ?

[Thanasis_3]

..also, the printer needs this type of wiring (see attachment)

[Thanasis_3]

Hello everybody!

I'm done with the printers!
I put a straight 3_wired cable (2 to 2, 3 to 3, 7 to 7) between the rj45_to_db25 adaptor and the printer and everything works fine,fortunately!!!!


Thank you all for the help.