Using the Parallel Port with Mach3.
Most computers nowadays are no longer provided with the old Cannon D type, 25 way, parallel port connector. Although this limitation can be overcome by installing a suitable PCI parallel port card there is a catch…
The old, original 5 Volt TTL standard (used in the days of parallel port printers) has to a large extent now been replaced with a new 3.3 Volt TTL standard. Many of our existing breakout boards and drivers etc. were designed for 5 Volts TTL operation and these older devices may not operate correctly with 3.3 Volt TTL.
When buying a new PCI parallel port card, unless you are confident that your existing equipment will work with 3.3 Volt TTL, then, to be on the safe side, always get a PCI card which provides 5 Volt TTL outputs.
How do you tell the difference ?
Please refer to the following diagram (thanks to Phame)…
Firstly, ensure that your PC motherboard does in fact have a 5 Volt PCI slot.
Next choose a PCI card which has the correct cut-out position for the 5 Volt PCI slot.
This may not be a totally fool-proof method of choosing the correct 5 Volt PCI card but it at least lets us identify the 3.3 Volt cards.
One final note – the parallel port can only be used with operating systems up to (and including) Windows 7 and it cannot be used with any 64 bit operating systems.
Tweakie.