USB to RS232

[696796]

Hi,

Does anybody know if using a USB serial adapter replicates the use of a serial port on a desktop.

The reason i ask is that i have done some programming using the comm port on my desktop. My laptop does not have a comm port, so will a comm port usb adaptor work in the same way i.e., can i 'open the port', 'close the port'.

Any help or suggestions where to look are much appreciated...

Alex

 

[Enndiem]

As far as I know, you can. I work for a company that designs serial interface cards and many of my laptop-using coworkers use usb-RS232 on a regular basis for testing. I can't imagine it wouldn't work like a standard com port.

 

[garebo]

I'm not the last word on this issue, but i have had a few experiences with usb serial adaptors. The weird thing is that sometimes they work and sometimes they dont. I can only suggest you stay with a name brand like Belkin or Tripp-lite, etc.

http://www.usbman.com/

http://www.lvr.com/usb.htm

http://www.usb.org/home

The intel site has specs you might be interested in:

http://www.intel.com/technology/usb/

Good advice + great people = tek-tips

 

[Sympology]

I use a USB to Serial converter and have never have had a problem. However saying that I only use it to conect to Network and Telecoms hardware, so cannot comment on how reliable they are for say modems and printers.

The advantage I find is Nortel and Cisco switches use diifernt PIN outs (Null and Straight) so always had to carry to cables. Now I can change the virual pin outs on the fly, so only need the one.]

Stu..

Only the truly stupid believe they know everything.
Stu.. 2004

 

[pawshman]

no probs at all

I use a USB->rs232

make sure that you keep the DRIVER that is provided or that one is provided, without the driver it wont work,

I'm using Xp and that plugs and plays the lead but wont work unless the right driver is loaded

 

[696796]

Thanks very much everyone,

I need to use mine so that i can connect a scanner and control it through .net code.

I think i'll go for a mainstream connector, Belkin or something.

Actually if anyone reads this....

CAN you get USB ---> S-Video cables?

Alex

 

[garebo]

I dont know the answer to that but you can likely google usb to svideo and get an answer.

Good advice + great people = tek-tips

 

[bcastner]

Conversion of any port to USB is a bad idea.
Conversion of USB to any other port is another bad idea.

Some applications will accept this.

But conversion is a bad idea. Purchase an adapter with a native port of they type you need. For laptop/notebook users, adding USB with a PCMICIA adapter is a bad idea.

 

[696796]

A bad idea? I thought it was a good idea so that newer laptops can use peripherals with older style ports.

 

[rvnguy]

696796,

Was your request specific to programming for the USB port?
You can access the USB Bus but not with RS-232 calls. USB's capabilities mean that the interface is more complex than the older serial and parallel interfaces it replaces. Every USB device must respond to a set of standard requests and other events on the bus. These calls are specific to the USB Bus archeticture even if you are using a cloning device for RS-232 capability.

rvnguy

 

[696796]

Oh Ok, i see where you are coming from.

Yes i will be programming using a usb port. Have you had much experience with this? I am developing in vb.net and have used this to control the comm port before.

So will using a USB mean i need to go by USB rules. Do you know much about controling a usb port/recievins and sending data?

In that case it may be worth just buying a USB cable for my Scanner and plugging it directly in.

Thanks,

Alex

 

[rvnguy]

696796,

I am (slowly) converting pc intefaces to lab instruments from rs-232 to USB bus. USB provides for a more robust net'ing in a lab environ of instruments. To ease the set-up for lab tech's I am using HIDMaker to interface micro-controllers in instruments to the pc world for data collection/manipulation. This might be overkill for what you want. I recall looking at vb.net and seem to remember that it does not support control of the comm ports.????

I breifly looked at a couple of rs-232 to USB converters and it appears that they contain the firmware to do the conversion. I have not used these as I prefer to use native code vs converted (and not under my control) code of a converter. These might perform what you require and are not expensive to try.
Note: I believe "bcastner" meant this in a quote from him:
"Purchase an adapter with a native port of they type you need."

and not to try to write your own code to do this. If you are trying to dwnld data from a recorder of some type many of thses devices include sftware for this and many are "legacy" bound and look for a rs-232 port and if you do not have one an adapter will probably "not" correct this as the conversion takes place outside of the environ and the sftware never sees a rs-232. Depends highly on what you have and what you are trying to do with it.

Your ref to "scanner": If this is what you are interfacing to by all means just buy the cable. Your orig post made it appear that you wanted to prog and contol the port???

http://www.usb.org/

is a link for information.

rvnguy