On Sep 22, 2006, at 6:21 AM, Bennett, Bruce wrote:

Another choice? Yeah, in the past I have used a PCI serial port card w/4
ports... $$

Which is fine for a desktop, not so practical for a laptop. ): Yeah, I know there are PCMCIA solutions, too.

The SI Labs based devices can actually be re-programmed to bear a unique ID,
and from that can be made to enumerate in a specific order.

This is all a real weak point in the USB drivers.

The FTDI drivers for Mac OS X claim that, if the device has a serial number, the driver will use that serial number as the device special file name. I don't have one that's serial numbered, so I have not been able to verify. The FTDI tools for windows claims to be able to serialize a device if it isn't already, but I haven't tried that yet.

Offhand, I don't know of an OEM branded USB to serial that uses the SI Labs chip -

Not an OEM adapter, but the Sparkfun guys have a breakout board that has a USB B connector, the chip, and some headers for TTL level rs232. I'm using one now to power and interface a PIC/MX614 packet decoder.

http://www.sparkfun.com/commerce/product_info.php?products_id=198

Looks like SparkFun has also picked up an FTDI device:

http://www.sparkfun.com/commerce/product_info.php?products_id=718

Both those are assembled breakout boards, but they also have the chips fairly cheap if an SMT chip solves your problems.

BG Micro (online surplus place) has a device with the FTDI chipset. They don't advertise it as such, but I have one and found it to be so.

http://www.bgmicro.com/prodinfo.asp?prodid=COM1193

I've also seen a device using an FTDI chipset that's 100% enclosed in a USB A connector, with bare wires on the other end for TTL level rs232 as well as +5V and ground from the USB port. I think it was about $15 a copy, but I can't remember where I found it.


I realize most of these are parts, not packaged solutions, but if you're building something from a kit or from scratch, or don't care to hack at a piece of equipment, they can make some handy solutions. My favorite part is drawing power from USB, and eliminating both the power cord to the peripheral as well as the voltage regulation from the circuit.

In my experimenting I have stumbled across one poor solution that works for Mac OS X: Most of those drivers use something vendor specific in the device special file name, so if you use only one device from each vendor, the names are unique. |:

-Jason
kg4wsv

_______________________________________________
Xastir mailing list
Xastir@xastir.org
http://lists.xastir.org/cgi-bin/mailman/listinfo/xastir

Reply via email to