[Elecraft] KUSB for K3

[Leigh L Klotz, Jr.]

Linux uses vendor and product id as well, but there is wildcard 
matching, so the driver is loaded based on the match.  Linux has a more 
flexible architecture for USB hotplug, so it is up to the distribution 
or the upstream provider of the USB system to decide what driver to 
load, not the manufacturer of the peripheral.  Also, in Windows, what is 
called the "driver" is often a driver and an application program to be 
autorun when the device is detected.  For RS232 dongles, there is no 
application program, but for some device that happens to incorporate the 
same chip but wants to autolaunch an app, there is.

For example, the Vector Network Analyzer from Mini Radio Solutions uses 
such a chip to provide USB connectivity, although it is inherently a 
serial device.  When I plug it in to Windows, it uses a generic driver I 
had to manually install, and it maps the device to some random COM port, 
using a number that changes from time to time; sometimes it is COM11, 
sometimes COM13.  I have to find the init file for the VNA software and 
edit it.

When I plug it in to Linux, it gets assigned the next device number, and 
for some reason it seems stable, so I can leave the init file set as 
/dev/ttyUSB1.  (My K2 is on hardware RS232 port /dev/ttyS0 and my 
antenna controller on /dev/ttyUSB0).  If the MiniRadioSolutions people 
had gone all out, they could have gotten a special id and written 
something that runs their Visual Basic program automatically, but then 
upgrading it would have been a constant pain for hams who want to change 
it or try out other versions.  Still, not having to look for the COM 
port would have been nice, and that is mainly what the USB driver system 
in Windows tries to solve with its id system.  The price we all pay, 
though, is a complete failure for generic devices such as RS232 
converters.

When I put an SD card from my camera into my Linux box, it notices it, 
finds that it has a Win32 DOS filesystem on it, finds the driver, and 
mounts it as a filesystem.  Thw Gnome window system I run at home then 
notices the mounted filesystem, susses out the directory structure and 
guesses that is is from a camera (and not a USB memory stick for files 
or an MP3 player) and offers to start a photo edit/drag-and-drop tool.  
No manufacturer of camera or SD card was involved.  (I suspect the Mac 
does the same thing, only in a more refined way and with prettier 
icons.)

73,
Leigh/WA5ZNU
On Mon, 7 May 2007 1:41 pm, James austin wrote:
> Windows loads USB drivers based on the vendor id and product id 
> reported by the device. Are you implying that MacOS and Linux do it 
> differently, by saying the driver used is based on the chip?
>
> 73,
>
> Jim
>
>>
>> So, getting USB to work depends on the following:
>>
>> 1. the chip(s) implementing the USB port in your computer;
>> 2. the driver for the chip implementing the USB port in your computer;
>> 3. the chip(s) implementing the serial-to-USB adaptor;
>> 4. the driver provided with the serial-to-USB adaptor.
>>
>> If you are using a MacOS, Linux, or a flavor of UNIX you will find  
>> that there tend to be only a few generic drivers for this since the  
>> drivers are based on the chip(s) used. Windows requires a vendor- 
>> specific driver for each device. The latter means that even if you  
>> get the same hardware (serial-to-USB converter) from two different  
>> vendors (generic Taiwanese serial-to-USB adaptor), you need two  
>> different drivers for Windows but only one generic driver with MacOS,  
>> Linux, or *NIX.
>>
>> 73 de Brian, WB6RQN
>> Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com
>>
>
>
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