I have a printer with LPT port and it needs to be connected to serial COM1 port via adapter. Printer output is being rerouted to serial port COM1 with a command:

mode LPT1=COM1
mode COM1: 9600,n,8,1

and nothing is comming out. Is this possible to accomplish like on this picture in a link below? LPT to serial adapter picture

enter image description here

  • Never seen parallel to serial adapter, usually it is parallel to USB adapters. – Vojtěch Dohnal Jun 10 '16 at 11:25
  • @VojtěchDohnal Well, I have it and you can see it on the picture abowe. – Hrvoje T Jun 10 '16 at 11:38
  • 2
    Or is it indeed 25-pin to 9-pin serial adapter? I don't know now – Hrvoje T Jun 10 '16 at 11:58
  • It surely is, because it looks like no active chip is inside converting the paralel to serial, the real thing looks very differently and will work slowly youtube.com/watch?v=TX9AmbpGw6g – Vojtěch Dohnal Jun 10 '16 at 12:07

It is probably not a LPT to serial adapter. Serial port has 2 types of pinouts, of which the 25 pinout is practically the same as parallel port pinout, so you have probably only serial-serial connector instead of parallel to serial adapter. See also this answer.

The parallel printer can be connected to PC with USB cable that is called something like USB to Centronics Printer Cable.

For using the printer form DOS (under Windows) as LPT1 see this answer.

  • btw: it is not DOS in this case ;-) – Marged Jun 10 '16 at 13:26
  • @Marged - see the comments bellow another answer, yes it is a DOS program that runs under Windows. – Vojtěch Dohnal Jun 10 '16 at 13:31
  • What I meant was: technically it is not DOS which executes the program (although this can be a DOS program). But I didn't want to become too academical ;-) – Marged Jun 10 '16 at 13:32

I think that the adapter you show is a 25-pin to 9-pin serial adapter.

The 25-pin connector was originally developed as a serial interface, but for some reason PC manufacturers chose to use it for the parallel port.

Your adapter allows you to plug a cable with a 25-pin serial connector into the 9-pin connectors PCs use for serial ports, but the signals on the pins of a parallel port are completely different, so it cannot work and could have caused damage to the electronics on one end or the other.

Without a parallel port on your PC, your best bet, as @VojtěchDohnal suggests, is to use a USB to LPT converter, provided there is driver support for it in your OS. There may have been active LPT to serial converters at one time, but I doubt you'll find one now.

  • This printer is used under DOS directly, so I don't know would USB work there? Maybe USB to Centronics Printer Cable with some kind of emulation of USB on DOS? – Hrvoje T Jun 10 '16 at 11:57
  • @HrvojeT You mean DOS under Windows, surely not just DOS...? – Vojtěch Dohnal Jun 10 '16 at 12:04
  • If you're using DOS (I hadn't expected this), you need a real LPT connection. There may be one on your motherboard, in which case you need to find a back-panel socket with a cable to the motherboard connector. Otherwise, you may be lucky enough to find an interface card that you can plug in. You may be able to cannibalise an old PC if you can find one of a similar vintage. – AFH Jun 10 '16 at 12:25
  • Yes, it's DOS under Windows. The application that uses printer works only in DOS and uses LPT. I have one LPT connected to MBO, but I need two so I hoped I could use serial. It's desktop Lenovo Thinkcentre so normal PCI LPT card does not fit. I think the only solution would be Centronics to USB and then somehow reroute LPT to USB. – Hrvoje T Jun 10 '16 at 12:52
  • See superuser.com/a/182678/285900 – Vojtěch Dohnal Jun 10 '16 at 13:05

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