[aprssig] Error checking within APRS packets
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?
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...
> Guido IZ6RDB
> aprssig mailing list
> aprssig at tapr.org
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