A TNC2 (clone) question

[k***@public.gmane.org]

Hi  All:
I have an old MFJ1274 TNC. I'm thinking of
putting it, along with a radio and a gel cell battery, in a waterproof box
for use as a temp DIGI for SAR and similar such field use.

What
I know about the MFJ:
1: It won't work with APRSISCE/32 (my fav)
since it won't stay in KISS mode.
2: It'll require a new EPROM for
extended KISS operation. That's about $40-50 by the time it's all up and
running. There are better and easier ways to do that for the same
money.

My questions:
1: Will the MFJ1274 support the new
n-N paradigm? or will it need to be addressed by it's specific
callsign-SSID? (I know it's been upgraded to at least 1.2.9 firmware)

2: will the MFJ even function as an APRS DIGI? (my understanding
is that there's nothing special about an APRS packet as far as a DIGI is
concerned)

Thanks and 73  KC8SFQ  Ron

[Tom Hayward]

1: Will the MFJ1274 support the new n-N paradigm? or will it need to be
addressed by it's specific callsign-SSID? (I know it's been upgraded to at
least 1.2.9 firmware)

No; yes.

2: will the MFJ even function as an APRS DIGI? (my understanding is that
there's nothing special about an APRS packet as far as a DIGI is concerned)

It will digi its own callsign and alias. The downside to this is if
you want to do it by callsign, you need to have all of your SAR
personel reconfigure their trackers when the portable digi is turned
on, and again reconfigure all of their trackers when the portable digi
is taken down, runs out of batteries, etc. Or, you could set the alias
to WIDE1-1, but you don't have callsign substitution; this is poor
form on APRS when there are so many affordable options available that
will do proper digipeating with callsign substitution.

If I were to build a SAR digipeater, it would be with a
Tracker2:http://www.argentdata.com/products/tracker2.html

Have your SAR personnel set their trackers to WIDE1-1,WIDE2-1,SAR7-7.
Configure the Tracker2 to preempt on SARn-N. This way, the trackers
still get into the normal network if available. When you have a SAR
network in place, it will digipeat your SAR trackers but not the rest
of the stations on 144.39.

Tom KD7LXL

[k***@public.gmane.org]

Post by Tom Hayward
you need to have all of your SAR
personnel reconfigure their trackers when the portable digi is

turned

Post by Tom Hayward
on, and again reconfigure all of their trackers when the

portable digi

Post by Tom Hayward
is taken down, runs out of batteries, etc.\

Well, Rats!! That was my suspicion though. I WAS hoping, but not
really surprised. The 1274 is getting a little long in the tooth, but it
still works.

Post by Tom Hayward
If I were to build a SAR digipeater, it would

be with a
Tracker2:http://www.argentdata.com/products/tracker2.html

I
have one OT2 already, but it is dedicated to the truck so I can have
mapping and messaging. APRS is, after-all, all about situational awareness
on the move.

Post by Tom Hayward
Have your SAR personnel set their trackers to

WIDE1-1,WIDE2-1,SAR7-7.

Post by Tom Hayward
Configure the Tracker2 to preempt on

SARn-N. This way, the trackers

Post by Tom Hayward
still get into the normal network

if available. When you have a SAR

Post by Tom Hayward
network in place, it will

digipeat your SAR trackers but not the rest

Post by Tom Hayward
of the stations on

144.39.

I had seen a discussion to this affect before, and it
is precisely the functionality I am striving for. I want my porta-digi to
intigrate seamlessly and transparently into, and out, of the system
without having to reinvent the wheel every time something changes.

I guess I'm still looking for a wagon for the old war-horse of an
MFJ to pull.

Thanks, Tom.
73  KC8SFQ  Ron

[Stephen H. Smith]

I have an old MFJ1274 TNC. I'm thinking of putting it, along with a radio and
a gel cell battery, in a waterproof box for use as a temp DIGI for SAR and
similar such field use.
1: It won't work with APRSISCE/32 (my fav) since it won't stay in KISS mode.
2: It'll require a new EPROM for extended KISS operation. That's about $40-50
by the time it's all up and running. There are better and easier ways to do
that for the same money.

Replace the eprom with the last-ever TAPR Release 1.1.9 firmware which has a
perfectly serviceable KISS implementation in it.

1: Will the MFJ1274 support the new n-N paradigm? or will it need to be
addressed by it's specific callsign-SSID? (I know it's been upgraded to at
least 1.2.9 firmware)

Not as-is, with the exception that if all you want it to do is be a home-style
first-hop fill-in digi, then set it's callsign "alias" to "WIDE1-1" . (The
first-hop WIDE1-1 digipeating doesn't depend on the TNC having the
APRS-centric callsign-changing/substituting capability described below.)

2: will the MFJ even function as an APRS DIGI? (my understanding is that
there's nothing special about an APRS packet as far as a DIGI is concerned)

But there ARE major differences between classic connected packets and APRS
packets !

From the standpoint of the AX.25 protocol used by both "classic" packet and
APRS, the path settings are the callsign(s) of the station(s) being asked to
relay the packet. In classic packet, these would be the actual calls of the
stations involved; i.e. you had to know in advance the calls of the stations
involved to get a packet relayed. In APRS, all stations respond to the same
generic "callsigns" of WIDE1-1, and/or WIDE2-n.

Current "New Paradigm" APRS depends on digipeaters being able to actually
CHANGE these "callsigns" as packets pass through them -- something classic
packet NEVER did. APRS digis modify these "calls" as they pass the packet
on, to track and control the number of relay hops. For example, WIDE2-2
becomes WIDE2-1 which becomes WIDE2-0 as a packet passes through 3 successive
digis. This handling of callsigns is unique to APRS.

Many of the new-breed low-cost KISS-only APRS-only TNCs such as TinyTrack 4,
Tracker2, TNC-X, AGW uTNC, etc CAN do APRS-style digipeating stand-alone.
The ONLY "classic" TNCs able to do this off-the-shelf stand-alone (i.e.
unassisted by computer programs), were the Kantronics KPC3 family TNCs.
PK-232s, TNC2s, etc require a computer program running through a KISS interface
to do modern APRS digipeating.

You can endow almost any TNC-2 clone, such as your MFJ with this ability by
replacing it's OEM firmare with the freeware UI-Digi firmware that converts the
TNC2 to a dedicated APRS digipeater. However it becomes STRICTLY a stand-alone
digipeater, and can no longer be used for local transmit/receive by a an
attached PC.


See the full history and underlying logic of APRS digipeating here on my website:

"APRS 101" Explanation of APRS Path Selection & Digipeating
http://wa8lmf.net/DigiPaths

-------------------------------------------------------------------------------

--

Stephen H. Smith wa8lmf (at) aol.com
=== Now relocated from Pasadena, CA back to 8-land (East Lansing, MI) ===
Skype: WA8LMF
Home Page: http://wa8lmf.net

===== Vista & Win7 Install Issues for UI-View and Precision Mapping =====
http://wa8lmf.net/aprs/UIview_Notes.htm#VistaWin7

*** HF APRS over PSK63 ***
http://wa8lmf.net/APRS_PSK63/index.htm

[Lynn W. Deffenbaugh (Mr)]

For example, WIDE2-2 becomes WIDE2-1 which becomes WIDE2-0 as a
packet passes through 3 successive digis.

A bit nit-picking here, but I count only TWO digis in the example. The
first hears the WIDE2-2 and transmits a WIDE2-1. The second hears the
WIDE2-1 and transmits the WIDE2-0 which is more commonly shown as WIDE2
(lack of a -SSID implies -0). In addition, the second digi should also
set the "used" bit in the AX.25 header because it decremented to zero
which is typically then shown as WIDE2*.

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

[Stephen H. Smith]

For example, WIDE2-2 becomes WIDE2-1 which becomes WIDE2-0 as a packet
passes through 3 successive digis.

A bit nit-picking here, but I count only TWO digis in the example. The first
hears the WIDE2-2 and transmits a WIDE2-1. The second hears the WIDE2-1 and
transmits the WIDE2-0 which is more commonly shown as WIDE2 (lack of a -SSID
implies -0). In addition, the second digi should also set the "used" bit in
the AX.25 header because it decremented to zero which is typically then shown
as WIDE2*.

I was actually thinking about the WIDE1-1.WIDE2-1 scenario for three hops when
I wrote this, and forgot about the WIDE1-1 part......

[Stephen H. Smith]

Post by Stephen H. Smith
I was actually thinking about the WIDE1-1.WIDE2-1 scenario for three hops
when I wrote this, and forgot about the WIDE1-1 part......

Arrrgh! Screwed it up again responding too fast!

I meant to say "WIDE1-1,WIDE2-2 scenario" .

[Steve Daniels]

Argent data will program a KISS rom for $5, they will also program a UIDIGI
rom for free to encourage digipeaters. Using a 27C256 rom.

At a guess they would probably program other digipeater firmware for free.

You need to supply the code you want programmed however.

https://www.argentdata.com/catalog/product_info.php?products_id=24

I have both roms for a tnc2 clone from them



Steve Daniels

G6UIM

Torbay Freecycle Moderator

_____

From: aprssig-bounces-***@public.gmane.org [mailto:aprssig-bounces-***@public.gmane.org] On Behalf
Of Stephen H. Smith
Sent: 14 November 2011 17:18
To: TAPR APRS Mailing List
Subject: Re: [aprssig] A TNC2 (clone) question



On 11/14/2011 9:24 AM, kc8sfq-***@public.gmane.org wrote:


Hi All:
I have an old MFJ1274 TNC. I'm thinking of putting it, along with a radio
and a gel cell battery, in a waterproof box for use as a temp DIGI for SAR
and similar such field use.

What I know about the MFJ:
1: It won't work with APRSISCE/32 (my fav) since it won't stay in KISS mode.
2: It'll require a new EPROM for extended KISS operation. That's about
$40-50 by the time it's all up and running. There are better and easier ways
to do that for the same money.


Replace the eprom with the last-ever TAPR Release 1.1.9 firmware which has a
perfectly serviceable KISS implementation in it.





My questions:
1: Will the MFJ1274 support the new n-N paradigm? or will it need to be
addressed by it's specific callsign-SSID? (I know it's been upgraded to at
least 1.2.9 firmware)


Not as-is, with the exception that if all you want it to do is be a
home-style first-hop fill-in digi, then set it's callsign "alias" to
"WIDE1-1" . (The first-hop WIDE1-1 digipeating doesn't depend on the TNC
having the APRS-centric callsign-changing/substituting capability described
below.)





2: will the MFJ even function as an APRS DIGI? (my understanding is that
there's nothing special about an APRS packet as far as a DIGI is concerned)


But there ARE major differences between classic connected packets and APRS
packets !

Post by Stephen H. Smith
From the standpoint of the AX.25 protocol used by both "classic" packet and

APRS, the path settings are the callsign(s) of the station(s) being asked
to relay the packet. In classic packet, these would be the actual calls of
the stations involved; i.e. you had to know in advance the calls of the
stations involved to get a packet relayed. In APRS, all stations respond to
the same generic "callsigns" of WIDE1-1, and/or WIDE2-n.

Current "New Paradigm" APRS depends on digipeaters being able to actually
CHANGE these "callsigns" as packets pass through them -- something classic
packet NEVER did. APRS digis modify these "calls" as they pass the packet
on, to track and control the number of relay hops. For example, WIDE2-2
becomes WIDE2-1 which becomes WIDE2-0 as a packet passes through 3
successive digis. This handling of callsigns is unique to APRS.

Many of the new-breed low-cost KISS-only APRS-only TNCs such as TinyTrack 4,
Tracker2, TNC-X, AGW uTNC, etc CAN do APRS-style digipeating stand-alone.
The ONLY "classic" TNCs able to do this off-the-shelf stand-alone (i.e.
unassisted by computer programs), were the Kantronics KPC3 family TNCs.
PK-232s, TNC2s, etc require a computer program running through a KISS
interface to do modern APRS digipeating.

You can endow almost any TNC-2 clone, such as your MFJ with this ability by
replacing it's OEM firmare with the freeware UI-Digi firmware that converts
the TNC2 to a dedicated APRS digipeater. However it becomes STRICTLY a
stand-alone digipeater, and can no longer be used for local transmit/receive
by a an attached PC.


See the full history and underlying logic of APRS digipeating here on my
website:

"APRS 101" Explanation of APRS Path Selection & Digipeating
http://wa8lmf.net/DigiPaths

_____


--

Stephen H. Smith wa8lmf (at) aol.com
=== Now relocated from Pasadena, CA back to 8-land (East Lansing, MI) ===
Skype: WA8LMF
Home Page: http://wa8lmf.net

===== Vista & Win7 Install Issues for UI-View and Precision Mapping =====
http://wa8lmf.net/aprs/UIview_Notes.htm#VistaWin7

*** HF APRS over PSK63 ***
http://wa8lmf.net/APRS_PSK63/index.htm