[aprssig] Error checking within APRS packets

Guido Trentalancia iz6rdb at trentalancia.com
Tue Jun 21 11:48:43 EDT 2011

Hi Keith !

I am in a terrible rush at the moment, but I will try to give at least a 
first quick answer...

On 21/06/2011 06:45, Keith VE7GDH wrote:
> Guido IZ6RDB wrote...
>> Well, of course, otherwise they would be called "broken TNCs". I am 
>> referring to commercial ones, as otherwise they won't survive that 
>> long on the market.
> Well, there is the KPC3+ from Kantronics. That's a well known and very
> popular brand. I have about half a dozen or so of them. We all know how
> "broken" they are in KISS mode.
>> In fact, if something wrong happened or will ever happen, the most 
>> likely cause would be a local misconfiguration (especially if it's 
>> some widely used or well trusted commercial TNC).
> I think you are pointing the finger at UI-View here. If this was a 
> general
> problem, there would be thousands of people with the problem.

At that specific point I was thinking of TNC misconfiguration I suppose. 
And as for UI-View, I already told you in a previous message that I have 
never used it but any piece of software runs in a different environment 
(e.g. OS with different configurations and peculiarities) with different 
configurations (of the software) and different devices connected (with 
different configurations and versions, such as those of TNCs).

In any case the configuration is created by the user and out of the 
thousands of users, each one would have a different one in principle. 
For example, suppose that UI-View also has configuration parameters to 
set up the TNC upon starting up and the user has a Kenwood TNC and the 
user has entered PASSALL=enabled in the UI-View configuration (relative 
to the TNC), that is the end of the game, for that particular user and 
not for the remaining thousands of users.

>> So if that is happening only over APRS-IS, it should be a problem of 
>> the specific APRS IGate software and environment (either a 
>> misconfiguration or a bug).
> I can't think of any software that has a setting that would allow a "mis
> configuration" like this that would introduce errors.

See above. It is absolutely very common that APRS software has options 
for configuring the TNC. For example, I have tried Xastir and it has 
options that are passed 1:1 to the TNC over serial at startup.

> We can speculate, but some specific testing should pin down the caused.

Yes. Suppose one doesn't know anything or doesn't know where to start: 
try another IGate software with the same TNC and then try another TNC 
with the same IGate software. Then further narrow down...

Because this specific person eventually does not appear to be on this 
list, it all becomes more difficult for the rest of us to help out.

> 73 es cul - Keith
> ve7gdh at rac.ca


Guido IZ6RDB

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