| ??? 04/23/05 20:47 Read: times |
#92246 - USB RS232 interface quality issues Responding to: ???'s previous message |
Andy Neil said:
Neil Kurzman said:
Also note that diffent USB ports on the same computer get different numbers. This depends on the drivers and/or the adaptors. Some will give you the same COM: number irrespective of which USB port you use; others give different COM: numbers for different USB ports. I think the cheaper ones tend to do the latter. I seem to remember reading something about this, and as I recall, it has something to do with the need for an embedded serial number in ROM somewhere. For devices that lack such serial numbers, you end up with a different COM port number every time you plug the device into a different USB port. Also, some won't let you have more than 1 adaptor of the same model on the same PC. :-(
Again, I think this tends to be a feature of cheaper products? So, if you're going to want to use multiple USB-to-RS232 adaptors on the same PC, be sure to specify this when ordering! Or buy a multi-port adaptor - but, unfortunately, these seem to be disproportionately expensive :-( I am under the impression that these USB-to-RS232 converters vary greatly in quality. In a moment of desperation, I ran out to RadioShack and got one of theirs a few months ago. What a horrible piece of equipment! Outside of getting a new COM port number every time I plug it into a different port, the driver is highly unstable and crashes my system regularly. I can't even fully quantify what all this thing does wrong, but my serial-enabled applications seem to work much less reliably when using this thing instead of a native COM port. The bottom line is that this device just does not manage to behave quite like the real thing. I am looking for a good USB-to-RS232 device, and would be interested in hearing suggestions on particular models that work well under XP. I have been tempted to try a FTDI/DLP US232B for a single port device or a Comtrol RocketPort USB Serial Hub II for a multiport device. Has anyone tried these? I've had exceptional experiences with Comtrol PCI-to-RS232 cards in the past; the hardware and drivers are absolutely rock solid, and the RS232 implementation is excellent... I wonder if similar quality can be expected from this device. --Sasha Jevtic |
| Topic | Author | Date |
| Problem in Laptop... Please help~ | 01/01/70 00:00 | |
| MSComm is for Comm Ports | 01/01/70 00:00 | |
| Here's what I use | 01/01/70 00:00 | |
| The Joy of Windows | 01/01/70 00:00 | |
| No drivers required. | 01/01/70 00:00 | |
| Every USB RS232 Adapter ..... | 01/01/70 00:00 | |
| Drivers | 01/01/70 00:00 | |
| USB <--> serial adapter manufacturers | 01/01/70 00:00 | |
| USB to serial | 01/01/70 00:00 | |
| Depends! | 01/01/70 00:00 | |
| USB <-> RS232 interface quality issues | 01/01/70 00:00 | |
| Comtrol Products.... | 01/01/70 00:00 | |
| USB to serial fun | 01/01/70 00:00 | |
| Virtual Serial | 01/01/70 00:00 | |
| More fun... | 01/01/70 00:00 | |
| EEPROM | 01/01/70 00:00 | |
EEPROM | 01/01/70 00:00 | |
| Handshaking with usb to serial | 01/01/70 00:00 | |
| UB Serial Handshakes | 01/01/70 00:00 | |
| RS485 & USB->serial | 01/01/70 00:00 | |
| PL2303 | 01/01/70 00:00 |