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[aprssig] The ideal APRS digi

John Kraus jfkraus3 at cox.net
Mon Sep 27 00:02:19 UTC 2004

This could also be a prime use for Digi_Ned.  If I am correct Digi_Ned can 
receive on multiple ports and cross connect the ports and packets while 
doing n-N. It may even be possible to have the packet identified by port on 
the output.

Perhaps Henk will add some insight soon.

At 07:52 PM 9/26/2004, you wrote:
>Robert Bruninga wrote on 9/26/2004, 4:18 PM
>  > To clarify what I am proposing for APRS alt-input digis:
>  >
>  > The ideal APRS digi should consist of:
>  >
>  > 1) RX/TX on 144.39 connected to good APRS style TNC
>  > 2) RX on alt input channel for locals using any RELAY-only TNC
>  > 3) External Carrier Detects cross connected between TNC's
>  >
>  > See the drawing at: http://www.ew.usna.edu/~bruninga/digi.gif
>You might note that this setup has EXACTLY the same
>configuration/integration/DCD issues as adding a Mic-E function to a
>voice repeater; i.e. additional RX on a non-144.39 channel while
>providing TX holdoff until 144.39 is clear.
>I have wrestled with this issue for some time now since no
>currently-available dual-port TNCs support 1200 baud on BOTH ports.
>One thought I have had about an inexpensive way to implement this would
>to use a TNC-X with the serial RX-data-out line connected directly back
>into the serial TX-data-in line. (Since the TNC-X exclusively uses KISS,
>the retransmission would be an exact duplicate of the transmission
>received.  The CD and XCD lines would be cross-connected between the two
>TNCs as in Bob's diagram
>Unfortunately, it would also not have the digi's call inserted, or
>WIDEn-N decremented, but it would probably be the cheapest way to go
>(except possibly an old TNC-2 clone with a UI-Digi firmware brain
>transplant).  Presumably the digi's primary on-channel TNC beacons would
>statisfy the legal requirements for ID.
>Stephen H. Smith                   wa8lmf (at) aol.com
>Home Page:                            http://wa8lmf.com
>aprssig mailing list
>aprssig at lists.tapr.org

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