parport pin 01, 14, 16 and 17 no output

I want to use a PC that does not have its own parallel port, so I bought a dual parallel port PCIe card. I have been testing this card with the parport testing program that can be found on the linuxcnc wiki (porttest).

To see if all of the output pins are working, what I did is connect a wire between pin 15 (input) and one by one to each of the output pins. When clickig the corresponding output pin button, I could see the input 15 led turning from red to green, which shows me that the corresponding output is OK.

This test turns out to work fine for pins 2 to 9, but not for pins 01, 14, 16 and 17. Reading the linuxcnc doc, when the port is configured as output, those pins should also work as outputs...

The port is configured as output, I cannot configure ECP or other modes via BIOS since the PC itself does not have parallel ports

Any suggestions on how to make those pins work as output ?

The dual parport is of the NetMos PCI 9865 type.

Are you probing the port directly or using a breakout board? It is possible a pull up resistor might be necessary to make those outputs work right with the input.

it first I was probing directly, then I measured with a Multimeter. I get 3,25V on pins 2 to 9 and nothing at all on pins 1, 14, 16 and 17...

As I mentioned in my first message, I am trying to install a dual parallel port PCIe board, and cannot get to make the pins 1, 14, 16 and 17 work as outputs.

Until now I only had the PCIe board with its on-board connector installed. Today I also installed the second connector with the ribbon cable connected to the PCIe board and measured again with following results:

Parallel Port at 0x1100, the one directly on the PCIe Board:
when the outputs are OFF in HAL, pins 2 to 9 measure 0.0 V and pins 1, 14, 16 and 17 also 0.0 V
when the outputs are ON in HAL, pins 2 to 9 measure 3.25V and pins 1, 14, 16 and 17 0.0 V

Parallel Port at 0x1110, the one with the ribbon cable:
when the outputs are OFF in HAL, pins 2 to 9 measure 0.002 V and pins 1, 14, 16 and 17 also 0.002V
when the outputs are ON in HAL, pins 2 to 9 measure 3.25 V and pins 1, 14, 16 and 17 measure 0.164V

So at least on the 2nd parallel port, those outputs show some reaction when activated, but still unusable. Any idea how to proceed with this ?

Is 3.25 V on the other ports sufficient to work effectively ? They seem to be OK at least to be detected by the HAL input pins.

Between the 2 parallel ports, I do have enough inputs and outputs so I could easily ignore this problem, but somehow I would like to know why this is happening

As Todd mentioned, I'll bet you need a pullup resistor on those pins to see any change
(unless you can figure out how to set the port in EPP mode or some other mode that enables the push-pull drivers for those pins)

You may find that once you connect a breakout board everything just works.
Most decent quality breakout boards have the proper pull-up or pull-down resistors needed built in, rather than relying on the often marginal (and/or defective) push/pull of many parallel ports.

The breakout board is the next problem I am facing: I want to connect my CNC router to Linuxcnc. Currently it is controlled by a Richauto pendant that is connected to a breakout board with a 50 pin scsi type cable. I would like to be able to maintain this card and be able to switch between the pendant and linuxcnc at any time, so my idea was to make a breakout cable between the 25pin parallel port and the 50pin connector on the machine.

I already have breakout connectors for both, but I am not sure if I can just simply connect them as is, or if some interfacing is necessary.

I could make out the following on my controller card:

• X, Y, Z home sensors and Tool touch Sensor are connected via a PS2801-4 optocoupler
• Spindle Speed control is done with 4 digital outputs (one on-off and 3 lines to select up to 8 different speeds): those go from the pendant to the inputs of a ULN2803AC high current darlington (TTL to high current)
• Stepper signals from the pendant go to the inputs of several 26LS32AC receivers, so the X, Y and Z pulse and direction signals are differential signals, 2 lines per signal

I guess both the home sensors and spindle speed control should be OK to connect directly since the inputs on the controller board are TTL, but I am not sure about the XYZ dir and pulse signals: since they are differential signals, I wondered if I could get away connecting one line of each to the corresponding output pins on the parallel port and the other line to ground... having near to no experience with electronics, this might be a very naive idea but one has to start somewhere...

What I call "the pendant" really is the microcontroller that controls the whole machine. It is a pendant-sized box with an LCD display and a USB port. You copy the g-code files from your computer on a USB stick, than plug that stick into this box, and load the program in the pendant. This pendant then sends all signals (steps, spindle speed) to the breakout board within the machine or recieves them from this breakout board (XYZ and tool touch sensors). It works really well and is easy to use but is rather limited compared to the possibilities of LinuxCNC. It also shows some signs of wear, so I would like to be sure to have an alternative the day it suddenly stops working.

My idea is not to use it at the same time as LinuxCNC. I would like to be able to disconnect the cable from this "pendant" and connect it to the computer with linuxCNC. So it is either the pendant or linuxCNC, and this is why I am trying to make this breakout cable, basically a cable that has on one end one or two db25 connectors and on the other end a 50pin mini scsi connector.

I could of course forget about the current config, throw out the pendant and the breakout board and go for something else that is easier to control with a parport or mesa card, but this is a machine I bought from someone who sold it because he had no more room for it and did not use it often enough to keep it. Now it is installed at my place and I sometimes still rent it out to him, so since he is used to the pendant, I would like it to be possible to switch between both.

By the way, why did you move away from the parport ? does it have performance limits compared to mesa cards ? I have been checking out those mesa cards, but kept away from them because I considered them too complex.