[aprssig] PIC processor for APRS info for D-STAR mobiles?

Scott Miller scott at opentrac.org
Mon Jul 7 23:42:20 EDT 2008

> There is no DV low-speed channel.  Please read my other post comparing your original Mic-E design and D-STAR.  That should clear this up for you.

That seems to be contrary to everything that Icom says about it.  Yes, 
there's only a single RF channel - we understand that.  But everything 
I've read says that 1200 bps of the stream is set aside for low-speed 
data, which is why the radios have RS-232 or USB - it's something like 
the D channel in an ISDN BRI line (which could carry X.25 in addition to 
ISDN signaling).

Now it sounds like maybe the Icom radios are using some or all of that 
channel to send pre-formatted GPS data.  Is that correct?  If so, where 
are the specifications for that?  Or is GPS data only provided by add-on 

> You consistently use this term "DV low rate channel".  Understand that there is no "DV low rate channel" (ref: recent post on this SIG).  There is only the DV bit stream.  This is an extremely important concept that you are apparently overlooking in your zeal to make this a data channel.

Please explain in more detail why this channel (the 1200 bps data 
portion of the D-STAR DV stream, not a separate RF channel, we 
understand that already) can't be used for arbitrary data.  Icom's 
marketing implies that it can.

> Please read my post demonstrating the basic comparison of D-PRS/D-STAR and your Mic-E concept.  If you are still confused, please contact me offline and I will try to explain that comparison.

Pete, I'm not sure if you're just not explaining it very well or if 
you're being intentionally obtuse, but I've tried to follow the 
explanation and Bob's not the only one who's not getting it.  Have a 
little patience with us, and I'm sure we can get it straightened out.

> Your words have been demeaning.  No matter how "honorable" your intentions are, if they are presented in a demeaning manner you turn away those people you most want to work with you.  Please leave this alone on the SIG as the damage has already been done.  If you want to discuss with me privately (and keep it private) about possible future communications with vendors regarding D-PRS, you are always welcome to correspond -privately-.

I've seen nothing demeaning from Bob.  He's got an idea and he's trying 
to figure out how to make it work.  You've had an aggressive tone 
throughout the discussion and I really don't know why.

But back to the bidirectional features Bob's talking about - I don't see 
why that's such a problem.  If you can generate output for an IGate, you 
can generate output for a GPS receiver (or HamHUD).  As far as I know, 
that's all Bob's talking about.  Instead of just sending your position, 
you're seeing the positions of others.

Now, it would certainly be nice to get some user-defined text onto the 
built-in displays on these radios if that can be done, but I'm still not 
clear on whether that can be done or not.

So can we all calm down a bit, back up a couple of steps, and make sure 
we're all talking about the same thing?


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