[AR1911]

I wouldn't be so quick to dis the parallel port. It has some unique capabilities specific to our needs that are hard to replicate with newer I/O choices. If you are on a budget, all the inexpensive hardware needs a parallel port.

Older PCs in excellent condition are easy to find, with licensed Windows XP. They are usually free. I picked up 2, configured both exactly the same, and dedicated one to running CNC machines, with the other as a spare. I also set aside a 2nd boot partition on both to load LinuxCNC. Network it to your modern Win 7/10 64-bit for your CAD/CAM software, and make some chips.

[A_Camera]

I wouldn't be so quick to dis the parallel port. It has some unique capabilities specific to our needs that are hard to replicate with newer I/O choices. If you are on a budget, all the inexpensive hardware needs a parallel port.

...like what??? An example would be very useful otherwise you sound like somebody who don't have a clue... As far as I know, parallel port is a dinosaur, has zero advantages over the more modern Ethernet based interfaces.

Older PCs in excellent condition are easy to find, with licensed Windows XP. They are usually free. I picked up 2, configured both exactly the same, and dedicated one to running CNC machines, with the other as a spare. I also set aside a 2nd boot partition on both to load LinuxCNC. Network it to your modern Win 7/10 64-bit for your CAD/CAM software, and make some chips.

The guy bought a Mach4 license and you want him to degrade to Windows XP just to be able to run parallel port? You must be joking.

[AR1911]

...like what??? An example would be very useful otherwise you sound like somebody who don't have a clue... As far as I know, parallel port is a dinosaur, has zero advantages over the more modern Ethernet based interfaces.

The guy bought a Mach4 license and you want him to degrade to Windows XP just to be able to run parallel port? You must be joking.

I normally would not reply to a post like this because of the belligerent attitude, but In this case I'll expand in case someone else is interested.

For someone doing a first conversion (like the OP), the Parallel port interface has a few advantages:
- the hardware is cheap. You can often do a complete conversion on an older small CNC machine for $100
- You get up to 25 discrete pins. You can trace signals with a cheap VOM.
- You get simultaneous output on each pins (parallel) rather than queued signals on a serial (USB) interface. No latency.

Is it technically superior to ethernet or USB? Of course not, but if you are getting your feet wet with your first CNC conversion, working with "this pin is X direction, this pin is X clock" helps a great deal understanding the process. For a non-EE hobbyist, this is very useful. "Benchtop machines" and "Mach3/4" seems to indicate most of the people here are not making a living with their CNC project.

Once you get the axes moving and the spindle spinning, and make some chips, it's easy to see where a dedicated motion controller might improve your setup. Right now I'm working with 2 lathes and a mill, all using Mach 3 but with different choices for BOB, drives and motors. If I run into limitations on any of them I'll be looking for something better. So far it hasn't happened.

Sure, you can skip all this and buy a Haas VMC and pay a guy to train you on it. That's an exaggerated extreme, but there will always be something technically superior to whatever we are using. Sometimes good enough is good enough.

Having said all that, if the OP is building his mill to make parts to sell, then by all means he should invest in the most current technology with the right cost/benefit ratio, and the fastest, most reliable path to making parts.

[A_Camera]

For someone doing a first conversion (like the OP), the Parallel port interface has a few advantages:

- the hardware is cheap. You can often do a complete conversion on an older small CNC machine for $100

I don't think that is correct information at all. What is included in a "complete conversion"? Just a PC? Perhaps you can do that for a $100 but I doubt it is realistic. After all, you MUST have a working PC with HD + screen + keyboard + mouse. Perhaps you can find one for $100 with all that if you are lucky, but about twice that money is more realistic for a working PC, if you want to use 32-bit hardware and OS.

- You get up to 25 discrete pins. You can trace signals with a cheap VOM.

Yes, well... you get that (or even more) with a motion controller also.

- You get simultaneous output on each pins (parallel) rather than queued signals on a serial (USB) interface. No latency.

Except that that is NOT the way a motion controller works. It is NOT a serial to parallel converter, it is a motion controller, so the output is simultaneous on each pin, even more than with a parallel port based system.

No latency? compared with what? Anyway, latency is really not an issue because motion controllers buffer the messages, so the pulse outputs are actually MUCH smoother and more evenly distributed AND at a much higher pulsing rate than you can ever do using a PC parallel port. When a parallel port (LPT) is used for stepper motor pulse generation the pulses are timed by Windows (or Linux) so the timing will not be as accurate as required for even and smooth motion compared with a motion controller. Pulses and the pauses between pulses will have varying times and as a result, the speed of the motors will not be smooth and constant in every situation.

Is it technically superior to ethernet or USB? Of course not, but if you are getting your feet wet with your first CNC conversion, working with "this pin is X direction, this pin is X clock" helps a great deal understanding the process. For a non-EE hobbyist, this is very useful. "Benchtop machines" and "Mach3/4" seems to indicate most of the people here are not making a living with their CNC project.

If you are not an EE (or similar) or not a self thought Linux expert than you better avoid Linux all together. It's really not a "plug and play" thing. This is even more the case for someone who is just getting his feet wet with his first CNC conversion. That person has most probably more Windows experience than Linux, can install software and recognize the HMI, orients fairly easy on the screen. The same person gets quickly lost in front of the screen of a Linux PC. He/she is going to need loads of support just to install Linux CNC, even if he/she manages to install Linux. So Linux would be the last thing I'd advice a total newbie to start with. It is an uphill and unless the person is interested in the learning Linux part, not just want to use his/her CNC than it is the wrong way to go.

Once you get the axes moving and the spindle spinning, and make some chips, it's easy to see where a dedicated motion controller might improve your setup. Right now I'm working with 2 lathes and a mill, all using Mach 3 but with different choices for BOB, drives and motors. If I run into limitations on any of them I'll be looking for something better. So far it hasn't happened.

How do you know anything about the advantages/limitations or what you are missing unless you have tried out the different options? Of course Linux can be used and of course a motion controller is not absolutely necessary, you can use the LPT as well, but if you don't see any advantages and believe that a motion controller is just an expensive LPT converter than you don't really know much about the advantages and differences.

I started with LinuxCNC and parallel port, UPGRADED to Windows XP, parallel port and Mach3... now running Windows 10 with Mach3 and UCCNC + UC300USB and UC300ETH and I assure you that there are huge advantages.

YMMV

[109jb]

...like what??? An example would be very useful otherwise you sound like somebody who don't have a clue... As far as I know, parallel port is a dinosaur, has zero advantages over the more modern Ethernet based interfaces.

I'll give you an example of an advantage of a parallel port interface over Ethernet - Price. You can get a parallel port card for a PC for about $10, or dig one out of an older PC for free. An ethernet solution may be "better", but how good do you need for a G0704 conversion. I have LinuxCNC on a old Pentium 5 desktop running a G0704 at 200+ IPM with no issues. What more than that is needed. My particular PC that I am using is a surplus PC that I got from a local business for free because they were upgrading. All it needed was a HDD and I have many of those. I also run GRBL but that is another story.

The guy bought a Mach4 license and you want him to degrade to Windows XP just to be able to run parallel port? You must be joking.

The OP never said that he bought Mach4. He only asked about the Mach4 parallel port interface. I don't see anywhere where he said that he bought it.

[A_Camera]

I'll give you an example of an advantage of a parallel port interface over Ethernet - Price. You can get a parallel port card for a PC for about $10, or dig one out of an older PC for free. An ethernet solution may be "better", but how good do you need for a G0704 conversion. I have LinuxCNC on a old Pentium 5 desktop running a G0704 at 200+ IPM with no issues. What more than that is needed. My particular PC that I am using is a surplus PC that I got from a local business for free because they were upgrading. All it needed was a HDD and I have many of those. I also run GRBL but that is another story.

The OP never said that he bought Mach4. He only asked about the Mach4 parallel port interface. I don't see anywhere where he said that he bought it.

I am so tired of this "price" argument as being an advantage. If $100 is an issue for someone than he/she chose the wrong hobby. Also... you get what you pay for. True in this case as well.

BTW, you can't really buy a PC for $10, not even without HD. Just a screen costs more than that if it is working... I know, I have heard that those old PCs are given away free, and that is true occasionally, but not everywhere and not for everyone. I have been throwing out some and kept some, but I think I'd have a problem if I wanted to buy one with screen, keyboard and mouse for $10. Also, can you really run 64-bit Linux on a $10 PC? I doubt that.

[109jb]

He said he's going by hoss's instructions Hoss use's Mach4

Hoss's instructions have been out there for a long time and he started with Mach3, only going to Mach4 in the past few years and using the PP plugin at that. Just because the OP is using Hoss's instructions doesn't mean that they can't be deviated from where necessary or desired.

I am so tired of this "price" argument as being an advantage. If $100 is an issue for someone than he/she chose the wrong hobby. Also... you get what you pay for. True in this case as well.

BTW, you can't really buy a PC for $10, not even without HD. Just a screen costs more than that if it is working... I know, I have heard that those old PCs are given away free, and that is true occasionally, but not everywhere and not for everyone. I have been throwing out some and kept some, but I think I'd have a problem if I wanted to buy one with screen, keyboard and mouse for $10. Also, can you really run 64-bit Linux on a $10 PC? I doubt that.

OK moneybags. You may get tired of the money argument, but to a lot of people $100 is a lot of money. I get tired of people discounting price as a valid reason that someone may choose a different course. $100 buys a bunch of end mills, stock to make stuff, or some other tooling. Saying someone chose the wrong hobby because they don't throw money around like it grows on trees is quite frankly a load of crap. You don't need to spend money on ethernet smoothsteppers, or Mach4 to enjoy CNC as a hobby. There are other ways to accomplish the same end without them whether you want to admit it or not.

Now the $100 difference you mention is a bunch of crap as well. Ignoring the computer itself, because whether going Mach3/4 or linuxCNC will require a computer, a parallel port card is $10 and LinuxCNC is free. Compare that to your ethernet solution. Mach4 is $200, and an ethernet smoothstepper is $180, for a grand total of $380 for software and the hardware needed to run it if using ethernet. Explain how this is just an extra $100. Now add the lower computer cost since LinuxCNC is happy on old hardware and the difference will be even greater. You may not consider $380 or even $100 a lot of money, but others do, and a parallel port can drive a cnc'd G0704 just fine. There are many out there doing exactly this very successfully

As for how much it really costs, the OP will need a computer of some kind no matter what direction he chooses. A more capable computer is required for Mach4 compared to LinuxCNC or Mach3 and windowsXP. So, the Mach4 computer will likely be more money whether used, or new. Either one will need a monitor so your BS about the monitor is moot unless you know a way that Mach4 can be run monitorless. Same goes for keyboard and mouse.

Will 64-bit Linux will run on a $10 or free computer? I don't know and I don't really care. What I do know is that LinuxCNC v2.7 installed from the live CD iso will run on a old computer that I got for free. I could care less if it is a 32 or 64-bit OS for this purpose, and I don't know if the Linux version installed from the live CD is 32 or 64-bit. You can doubt it all you want, but I run LinuxCNC v2.7 on my old Pentium 4, and it runs just fine. There was a typo in my previous post as I am actually running a Pentium 4, not a Pentium 5. Since I speak from direct experience and you are not, there can be no argument on this.

BTW, that computer I got for free did include a keyboard, 14" lcd monitor, mouse, and everything except for HD due to security concerns and I got 4 of them that way for free. I never said it was common, or that it was available everywhere, but was an example of how scrounging can work to save money that you apparently don't care about. How many people these days don't know someone that has an old computer laying in their basement gathering dust? As an experiment, I just called one person that I know that is not a computer savvy person and asked him if he might have an old computer I could have for an experiment and guess what? He does, and said he would be happy to give it to me. He doesn't know the specs, and it may or may not be suitable, but then again it may be just fine. Many people could just ask around and find one in their own circle of friends. Another check I just did was a craigslist search which turned up a Compaq Pentium 4 desktop which looks like the exact model I am using for my CNC for $25. Another craigslist search turned up a 15" LCD and another 19" LCD both for $5 each. $30 total for a complete system capable of running LinuxCNC and it already has a parallel port. I also found several complete Pentium 4 systems ranging from $40 and up. While you may be correct that not everyone can get a free system, pretty much everyone can get a cheap system that can run LinuxCNC.