Revolution Reading GPS Data

Phil Davis revdev at
Tue Mar 4 18:41:27 EST 2008

Graham Samuel wrote:
> Thanks Phil for that insight. I had a quick look at your link and 
> staggered back, appalled. 

It's pretty ugly.

> It reminded me of what a gentleman named Robert Lipe said to me on 
> another list when he thought I was trying to reverse engineer the USB 
> interface of my device (maybe I was - I had not considered Rev in the 
> equation at that stage and had even less idea what I was doing). His 
> advice started off:
>> Reverse engineering USB protocols from scratch is possible, but only
>> if you pass the entrance exam:
>> Repeatedly jam a fork into your left eyeball.    If, after about 40 
>> jabs, your
>> thought is "man, this is great - my right eyeball needs a piece of 
>> this action",
>> then reverse engineering USB protocols just might be your calling.
> I think I will just go back to sleep on this unless and until I can 
> find out something more about the device I wanted to interface with. I 
> suppose that I was seduced by the enormous number of USB-connected 
> devices that surround me - right here where I'm sitting I can count 2 
> digital cameras, a printer, a scanner, a hard disk, an ADSL modem, a 
> keyboard, three mice, a GPS training device, a SatNav, an Elgato TV 
> receiver, a webcam, a digital storage card reader and a data key. Who 
> knows what else I might find if I go into the other rooms in the house? 

Good night man! But wait... (looking around my office...) my own 
collection is bigger than I realized....

> And to think that the people who engineered them all had to write 
> drivers for PCs and Macs, and (no doubt) they are all different. 
> Compared to that, Rev programming seems so easy, doesn't it?

It makes me appreciate Rev all the more!
> Back to the day job.
> Graham
> On Tue, 04 Mar 2008 09:55:31 -0800, Phil Davis <revdev at> 
> wrote:
>> Hi Graham,
>> Graham Samuel wrote:
>>> --- snip ---
>>> It looks to me as if my wish to create better software for it (on a
>>> Mac primarily) is pretty much a dead end - although if I can get hold
>>> of a serial-to-USB converter I might be able to experiment a bit.
>>> BTW I wonder why Rev has never entered the world of USB - I don't know
>>> about Linux, but for PCs and Macs, USB appears to be a completely
>>> standard interface and one which has been mandatory on all models of
>>> machine for many years. There must by a USB API for these operating
>>> systems - is it much more of a challenge to RunRev than the many other
>>> things they've had to incorporate? I do believe there is at least some
>>> level of demand.
>>> Graham
>> You're certainly correct that USB is well-defined standard, evidenced by
>> the many uses of it on all computing platforms and beyond. And as you
>> might imagine, the USB standard is necessarily complex to do all it 
>> does.
>> Here's a good introduction to USB:
>> I manage development of a system that uses a USB HID input/output
>> device. The device has 9 backlit input keys whose lighted states and key
>> events are managed/handled by a Rev-based app. The Rev app has no direct
>> interface with the device driver; it interacts with the driver via a
>> pass-through background app that provides a socket interface to the Rev
>> app. On the Mac, the driver is actually a custom-built Kernel Extension
>> (.kext) file; on Windows it's the Win32 version of the libUSB
>> open-source library ( ). I imagine
>> there may be better ways to implement this, but it is what it is.  :o)
>> It's the way we found we could make it work when it was initially 
>> needed.
>> I know I haven't answered any questions here, but maybe it gives a
>> little perspective.
>> -- 
>> Phil Davis
>> PDS Labs
>> Professional Software Development
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Phil Davis

PDS Labs
Professional Software Development

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