USB to serial port

[stampman]

I just just got a new laptop for dnc and it does not have a serial port, I tried an adapter from usb to serial, but after testing, the program that I sent from my machine is not the same as what is on the screen, and it varies each time I send it.
Help please!!

[jmr]

Make sure your FIFO buffers are set either low or turned off. To do this
Right click on "my computer"
click on "properties"
Go to hardware tab
Click on "device manager"
Click the + in front of "Ports (COM & LPT)"
double click on the usb port
click on "port settings" tab
click on "advanced"
Move scroll bar all the way to the left for both Transmit Buffer and Recieve Buffer

If that does not solve the problem it is one of 2 things:
The flow control settings on the machine and pc may not match. Do you know that the software you are using works with the settings you are using on any other computer?
Or
Many USB to Serial devices do not work properly when you try to use them for serial communication to a machine. One device that I do know works well is StarTech.com model ICUSB232.

[DareBee]

Did your adapter come with serial port emulator software?
Should work fine if it did and your settings are correct

[cnc_ken]

Went through similar problems using a USB to SERIAL on a Heidenhain 426.
I bit the bullet and bought a PCMCIA to SERIAL card. Totally eliminated all my problems. If you've got an available PCMCIA slot it's well worth the money to get one. Got mine at GEEKS.COM.

[jsaltow]

USB to Serial converter cables are hit-or-miss.
Most are intended to connect to PDAs and not legacy RS-232 devices.

The PCMCIA Serial card is an excellent solution.
I have used Quatechs SSP-100 (1-port) and DSP-100 (2-port)
The com ports appear as native serial ports to the operating system
and your communication software.

[Dan Fritz]

A USB-to-serial adapter may have problems with handshaking, which will cause "Buffer overflow" alarms on the CNC. jsaltow is right when he says that the USB adapters are "hit-or-miss". Some of them work OK, some do not.

If you're getting corrupted data, look for a mis-match of the "Stop-bits" setting between your PCs serial port and the CNC. Most CNCs can be set for either 1 or 2 stop-bits, and the PCs serial port must be set the same or you can get some corrupted data.

[jmr]

that is correct - many of the USB-to-Serial adapter drivers are horrible and do not do flow control correctly. The one that I have used extensively with many types of controls is: StarTech.com model ICUSB232
It costs $35 or less where the PCMCIA slot type ones cost about 3 times as much.

[vpcnc]

I have tested many different types of USB to Serial adapters.
With Many different types of Notebooks.
What I found is that No one Brand Adapter works with every notebook.
It's a crap shoot to get the right adapter, right drivers for the right Notebook..

Through my testing I have had 100% success using the Port replicator or docking station for the brand laptop that I interface to.

Yes it's a lot more costly, but it works and save lots of headaches.

Also the USB to Serial Adapters aren't very good for Drip Feed.. You will have lots of problems if you are trying to drip feed using Xon Xoff with one of these adaptors.

When you find one that works, at best it will work for Upload / Download.