[aprssig] bad paths and digipeaters?

Brian B. Riley brianbr at mac.com
Tue Nov 30 10:14:39 EST 2004

Yessss ... you can always count on Wes ... "when in doubt, throw a Stamp at
it!" ... Johnston for a Parallax solution!! (Though he is mellowing a bit in
his old age, he did rather diplomatically add reference to PICs and Atmels
as an afterthought!)

 <way to go, Wes!>

Cheers ... 73 de brian, n1bq, underhill center, vermont

On 11/29/04 7:56 PM, "Wes Johnston" <aprs at kd4rdb.com> wrote:

> Here's an idea... if you use a kpc3 or similar type TNC as a digipeater, leave
> MON ON, and hook a basic stamp to the serial port.  The TNC will copy each
> packet to the serial port just before digipeating, right?  Have the basic
> stamp read the packet, count the hops and if it determines that the count
> exceeds the local custom, have it interrupt the PTT line to the radio.  It
> could pull a relay in to interrupt whilst watching the PTT pin from the TNC to
> release.  It would keep the relay pulled in until the TNC released PTT, the
> let the relay drop.  This would have the effect of allowing an external
> processor to interrupt the TNC's access to the radio.  Each basic stamp (or
> PIC, or ATMEL) could be programmed to respond, err inhibit, based on a
> different number of hops determined by the local sys op.

> As an example, a user sending out WIDE7-7 in a path would be digipeated by the
> kpc3 firmware.  But if this PTT interrupter saw WIDE7-3, and the digipeat hop
> limit was set to 3, then it would interrupt the PTT when the tnc tried to
> digipeat WIDE7-3.

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