[Elecraft] How 'bout a USB interface?

[Mario Lorenz]

Am 12. Jul 2002, um 16:52:10 schrieb John Clifford:

> I'm not thinking about at the computer end, I'm thinking about at the radio
> end.  The computer end is a no-brainer.

Why would that be ? Any USB Device would need a USB driver written for it on
the computer end.

> Why do I want USB?
> 
> * USB doesn't run into hardware conflicts on Windows boxes (or other boxes)
> * USB doesn't have gender/DTE-DCE aspects to worry about

Here you are mistaken. USB is a Master-Slave system, with the computer acting
as the slave, and many USB chipsets for USB devices (eg. for serial ports) are
NOT Master-capable.

> * Most modern PCs/operating systems/PDAs support it

Yes. PC's as Masters, PDA's usually as slaves only. My iPAQ has USB, but is
not Master capable, eg. I can NOT hang any USB->Ethernet or the like gizmos
on it (even though I'd very much like to...). On the other hand, on an
electrical level, serial ports are completely interchangeable. Connector/
Gender issues can be solved easily, especialy for someone who knows which
end of a soldering iron is the hot one...

> * USB is Plug and Play on these operating systems

Only if a driver for the device exists. That driver would have to be written
for all the major platforms...

> * USB doesn't require the user to know what serial port he is connected to

I regard that to be a disadvantage. Imagine two K2-USB's daisychained on the
USB port. It's more difficult to keep them appart in the software, because
you cannot simply trace which serial port that K2 is connected to...

> * USB allows for daisy-chaining of multiple devices (besides radios) and
> would allow
>   for simpler multi-radio configurations
> * USB allows multiple PCs/software to access the K2 simultaneously

Can you elaborate on that ? I'm not aware of any setups where two PC's share
one ressource via USB (I dont know if thats possible). As for multiple
pieces of Software, this is merely a software problem and can be solved for
serial ports, as well.


> For instance, it would be neat to set up a cheap PDA (used Palmpilot) to act
> as a super display/control panel for the K2 while still allowing for digital
> HF software (e.g, MixW) to control the K2.  Or... build a 'super display'
> into the EC2 box that would feature one of the available LCD flat panels for
> a super display/control.

See above. All those PDA's do have serial ports. Sometimes you need some
circuitry to adapt the voltage levels of the serial ports, but other than that
the serial port is interoperable and straightforward, whereas I could not name
a PDA that can act as an USB master. I know for sure my iPAQ can not. And
since this seems to be a limitation of the ARM CPU/Chipset, I doubt any other
ARM/SA11xx based PDA's can do that.

As for the possibility of hooking up several pieces of equipment ("Super
Display", "MixW control", whatever), this is ultimately an issue of the
protocoll spoken on the serial port. You can easily daisychain several pieces
via the serial wire, protocol permitting.

In short, I'm a strong advocate of the serial port, because its way simpler
in design. If someone really needs to hook it to a USB because his computer
doesnt support "legacy" interfaces anymore, theres always the cheap
USB->Serial boxen..

Mario
-- 
Mario Lorenz                            Internet:    <ml@vdazone.org>
                                        Ham Radio:   DL5MLO@OK0PKL.#BOH.CZE.EU
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