[aprssig] Error checking within APRS packets

Gregg Wonderly gregg at wonderly.org
Mon Jun 20 14:38:16 EDT 2011

Do we have any real examples of how the quiet TX 1/2 through packet followed by 
loud TX complete packet can result in a "packet" too long that would corrupt 
internal TNC buffers?

Will the start of the "loud" packet result in an end of packet recognition of 
the "quiet TX" packet.

How does all of this play out to indicate that there are failure modes that 
we've seen but not been able to identify the cause of?

Gregg Wonderly

On 6/20/2011 1:25 PM, Guido Trentalancia wrote:
> On 19/06/2011 13:57, Jason KG4WSV wrote:
>> On Sun, Jun 19, 2011 at 3:08 AM, Max Harper <kg4pid at yahoo.com
>> <mailto:kg4pid at yahoo.com>> wrote:
>>     What type of error checking does APRS have to prevent corrupt data?
>> APRS doesn't have any, but APRS is transmitted in AX.25 packets (on VHF,
>> anyway), and AX.25 has a 16 bit checksum (known as the FCS) to verify the data.
> And one day perhaps we should add the ability to also correct such errors ? For
> example, the day when we have all moved to speeds greater than 1200 (or at most
> 9600) bits/s...
>> -Jason
>> kg4wsv
> 73,
> Guido IZ6RDB
> _______________________________________________
> aprssig mailing list
> aprssig at tapr.org
> https://www.tapr.org/cgi-bin/mailman/listinfo/aprssig

More information about the aprssig mailing list