Since the release of Windows XP
many laptop manufacturers no longer have a "proper"
serial port at the back. Notable exceptions are quite recent
IBM Thinkpads and some Dells with the docking station. Instead
there are only USB ports. As a result users are finding that
a USB to serial adapter is the only way they have to communicate
with their CNC machines.
Unfortunately all USB convertors are not created equal, especially
if they contain the "prolific" chipset. Devices
intended for use at home are now expected to work in the harsh
industrial environment, and unfortunately many are not up
to the job. Many manufacturers of USB to serial adapters are
not 100% compatible and communication to with CNC machines
is either unreliable, very slow, or limited to one way transfer.
For a great technical explanation of the differences between
"proper" serial ports and a USB convertors, click
here.
For laptops we recommend you use a PCMCIA/Express to serial
card, they are far superior and often not much more expensive,
preferably with some form of isolation. We have several Quatech
cards and found them to be very reliable, in addition they
have all the required drivers for all versions of Windows.
If you must use a USB device, then we have used Keyspan USB
to RS232 adaptor cables - they work great when others just
don't >> Click
Here or Here
and are reasonably priced. We have reports from several users
that MOXA
are also reliable.
Please take time to watch this video for additional information
and resources about USB devices from BB-Electronics. This
company sells more robust rugged USB devices (albeit more
expensive) much more suited to industrial applications www.bb-elect.com.
Often it is worth spending more money initially, than wasting
time when you cannot get the USB to work.
Unfortunately it's not as simple as listing USB to RS232 devices
that work for one user, because sometimes the same one will
not work for another. So whilst we list several options above,
there is just no 100% guarantee that any will work with your
computer.
Quite often we think that it is well worth the while to buy
a secondhand laptop off ebay with a proper serial port. In
many cases this would work out cheaper and far more reliable
than having to buy things such as USBs or Express cards.
