[aprssig] What is "TNC Channel Switching"?

Ray Wells vk2tv at exemail.com.au
Sat Apr 12 17:29:34 CDT 2014

On 13/04/14 07:37, Stephen H. Smith wrote:
> On 4/12/2014 1:55 PM, Greg D wrote:
>> Stephen H. Smith wrote:
>>> However, many users still use the command-line mode instead, since 
>>> many older
>>> TNCs don't support KISS.   (Particularly the MFJ 127x series TNCs that
>>> crammed in numerous other modes, so that there wasn't enough room in 
>>> the
>>> 27256 eprom for KISS support.  I have replaced the OEM firmware on 
>>> countless
>>> MFJ 127x TNCs with the final release "official" TAPR 1.1.9 firmware 
>>> precisely
>>> to regain the KISS capabilities.)
>> Um, I have an MFJ 1278T TNC, and am running it in KISS mode under 
>> APRSIS/32.
>> Stock firmware on it, I believe, though I don't recall what version.
>> Greg  KO6TH
> That's a relatively late version of the MFJ-1270 family that (I think) 
> finally went to 27512 EPROMs instead the '256s of earlier versions and 
> consequently has a lot more room for code.
> The original MFJ-1270 and the MFJ-1274 that I still have came OEM with 
> KISS-less firmware.    I put the generic last-ever TAPR TNC2 V1.1.9 
> firmware in both instead, to regain the KISS mode.
> (I also hacked the eprom image to make the device power up defaulted 
> to full 8-bit 8-N-1 instead of the archaic default 7-E-1 serial port 
> settings, avoiding having to constantly init with AWLEN 8, 8BITCONV 
> OFF and PARITY 0.)
> __________________________________________________________________
My MFJ1270B TNC's (x5) all had 27256 OEM EPROMs that came with both 
native mode and KISS (with horrendous timing issues). I fitted them with 
KISS only EPROMs; end of timing issues and always in KISS mode. No more 
magic incantations to get into and out of KISS mode.

Ray vk2tv

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