[aprssig] TNC220s and KISS - Possible?

Dave Baxter dave at emv.co.uk
Thu Jun 29 04:23:39 CDT 2006

Hi Ian...

Yes, TNC220's can do KISS, you may need to update the firmware though.
V1.1.6D4 I use has KISS, and UiView is more than happy with it.  But you
have to be careful with the sequence of commands to set the serial link
baud rates etc, especially if like many of these now, the internal
memory backup battery has long since bit the dust.  There was a design
flaw, that drained the battery quickly, many were modded to fix that,
many were not.  I don't have the mod details any more, does anyone?

Otherwise, they are very good TNC's.  The AMD modem chip in particular
really flies with radio audio use.  Mine will successfully decode stuff
that is only just above the noise, unlike the thing in the D7's..

Start it in "Terminal" or "Host" mode, do all the serial and radio baud
rate settings there, remember to issue a "RESTART" command, change the
PC's serial speed (if needed) verify comm's then enter KISS mode, etc
etc....   Much of that is a lot easier with another terminal program it
has to be said.  I find that for 1200bd packet/APRS/KISS use, the link
to the PC should run at 4800bd, any faster, and there seems to be
problems somewhere.  Likewise if it runs at 2400bd or slower, you get
bottlenecks and delays etc when digi'ing.

If you can't get joy from PacCom for a replacement EPROM, let me know

Oh yes...  The hardware is not directly TNC2 compatible, so other
"generic" EPROM's wont run.  Thinking of things like DigiNed etc...  It
uses a Z80 (2MHz clock by default, but there were mod's about to up it
to 4MHz) but it also uses a SCC chip, not the SIO, or the other way
round, either way, it wont work with TNC2 clone code.   Check also yours
aren't modded for use as a satellite gateway, full duplex at 9k6.  If it
is, there could be a toggle switch on the back somewhere, from memory,
you'll need to figure out if it's not marked up, which way is "Normal"
and which is "Satellite".


Dave G0WBX.

> -----Original Message-----
> From: Ian ZL1VFO [mailto:zl1vfo at yahoo.co.uk] 
> Sent: Wednesday, June 28, 2006 10:32 AM
> To: aprssig at lists.tapr.org
> Subject: [aprssig] TNC220s and KISS - Possible?
> Hi all,
> Another ham & I have several PacComm TNC220s bought from 
> Market day sales over the years, however we have had little 
> luck getting them to run in KISS mode. UIView32 spits out 
> 'Break Errors' and 'Framing Errors', whereas AGWPE just locks 
> up & drives CPU usage to 100%.
> Normally this P166 runs happily at 2-5% talking to a TNC2 
> which does have KISS init.
> They appear to work fine in a normal terminal mode, though.
> Their boot up screen is as below.
> PacComm TNC-220 Packet Controller
> AX.25 Level 2 Version 2.0
> Features:
> Release P1.1.6B2  05/17/89 - 32K RAM
> Checksum $EA
> cmd:
> Would anyone know where one can buy EPROMs with a KISS mode 
> in them that will work with this model TNC?
> I'd also be happy with other generic or open-source KISS 
> enabled firmware, which I could download & burn myself (I 
> have a EPROM programmer).
> 73 de Ian ZL1VFO
> Auckland, NZ.

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