[Ham-Mac] Need Ideas on USB-Serial Problems

[wb6rse1 at mac.com]

> On Dec 15, 2007, at 1:14 PM, David Anderson GM4JJJ wrote:
>
> What version of Keyspan driver are you using?
>
> I'm using an Intel Mac with 10.5.1 and Keyspan 2.4 and I can  
> communicate between a dual Keyspan adaptor USA-28X and everything I  
> have hooked up including a Spid Rotator and MacDopper. Have you an  
> RS-232 LED test dongle that you can put in line and see if data is  
> being sent and received?
>
> I have had odd problems, but that was when I was using a USB hub  
> and the Keyspan, then sometimes the ports didn't get detected.
>
> 73

Me also. I have an Intel Mac Pro running 10.4. Previously had a G4  
also with 10.4. Ran a Keyspan through a hub and the G4. Using the  
same configuration on the Intel Pro, the Keyspan would not work.  
Eliminating the hub (Belkin) and connecting the Keyspan directly to  
the USB port on the front of the Pro (IE bypassing the hub) solved  
the problem.

The G4 only had USB 1.1. The hub is a USB 2.0 and supposedly  
backwards compatible.

Below is a summary of Keyspan's reply to me. FYI

Steve Muncy - I don't see you mentioning a hub inline but I thought  
this might be a useful adjunct to the discussion. And there have been  
changes in Leopard in terms of moving functions (and not documenting  
them) to new locations so calls become errors. Likely bringing a lot  
of "joy" to developers.

GL - Steve WB6RSE
_______

"This is a touchy subject that isn't really covered outside of Keyspan.

A hub 'should' support all USB devices.  It really depends on the  
quality of the hub.

Technically speaking, a hub should follow the USB spec.  If the hub  
doesn't follow the spec, they run into compatibility issues and  
performance issues like what you've seen.  When they don't, we see  
odd behavior like what you described.   If you find a hub that  
follows the USB spec, you won't have these issues.  Sadly, USB hub  
vendors whether or not they follow the spec.   You just have to try  
hubs until you find one that works with all of your devices.  We used  
to sell hubs that followed the spec but we've gotten out of the hub  
business.  With hubs changing day to day (not to mention that USB hub  
vendors buy their hubs and repackage them) it's hard for anyone to  
recommend a hub since the available hubs keep changing.

Our adapter is unique in the USB world because we take advantage to  
get the most USB performance so that serial communicate actually  
works like it does on older Macs.   Not all USB devices take  
advantage of USB like we do (in fact, few do) so you usually don't  
see these issues on run of mill printers, thumb drives, hard drives,  
etc because they don't need the exact timing of serial."