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VK2TV > TNC 20.08.07 23:59l 84 Lines 3451 Bytes #999 (0) @ WW
BID : 23775_VK2TV
Read: GUEST DK3HG
Subj: Re:TNC2 EPROMS
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Sent: 070820/2154Z @:VK2TV.#MNC.NSW.AUS.OC #:17639 [Kempsey, QF68JX] $:23775_VK
From: VK2TV@VK2TV.#MNC.NSW.AUS.OC
To : TNC@WW
# Generated by: TstHWin v2.21b - Registered to VK2TV
# On : 8/21/2007 7:54:15 A
# UTC: 8/20/2007 21:54:15
>From: ZL1ABS@ZL1AB.#06.NZL.OC
>To : TNC@VKNET
>
>TNC2 EPROMS
>
>With the recent discussions of "What TNC are you using?", the topic of
>using different EPROMs for firmware was mentioned.
>
>I have MFJ1270C TNCs with standard firmware EPROMs. I have obtained
>various EPROM images but haven't found anyone who can program EPROMs from
>the files. Like others I have a used EPROM copier (GP XP640), but no
>software to run it from a PC & be able to download an image file to the
>programmer.
>I can copy things fine with the built in keys on the programmer & even
>make changes by hand. Keying all the data in for an EPROM is a much work
>though.
>
>I once asked around if anyone had an EA EPROM programmer (uses parallel
>port) they didn't want & haven't found any. Either everyone is well
>satisfied with their EA EPROM programmer or they dumped it ages ago, HI.
>
>Lots of amateurs have PIC & ATMEL programmers now, but few plain old EPROM
>programmers.
>
>So if I can get a copy of a KISS EPROM for a MFJ1270C or TNC2, I'll be
>able to run off lots more.
>I can post anyone the first blank EPROM to get things started. I have my
>own 6 Watt clear glass, UV tube in a wooden box to re-use old EPROMs. It
>makes a purplish Octarine glow that's bad for the eyes.
>
>It is U23 (27C512) in the MFJ1270C that holds the firmware (V2.2 in the
>one I'm looking at). I can (& do) manually set KISS mode with the standard
>firmware, but there is always the chance of things reverting back to
>"normal CMD: mode" when there is a power cut or I turn my back & Murphy
>comes into the shack, HI.
Hello Michael and all,
I recently purchased an EPROM burner to replace my old unit that died after
about 15 years and am able to "burn" almost any EPROM from 2708 upwards.
I'd happily do one for you but I suspect the cost of postage from here to
ZL and back would make the exercise financially unviable.
I know Michael referred to the MFJ1270C, and that's a different beast to the
12870B. My comments that follow refer to the MFJ1270B, and probably any
other true TNC2 clone.
With reference to the KISS implementation in the standard EPROM that ships
with the MFJ1270B - it's marked TNC 2 1.2.8-32K - the timing is all over
the place. I had my TNC's trying to transmit over incoming valid data, not
transmit at all, introduce very long delays before transmitting, not
transfer received data to the computer. Damn terrible. I didn't have any
more luck with TAPR firmware for the TNC2. The problem wasn't restricted to
a single TNC, they all did it.
The lights on the TNC are status indicators in KISS mode. The STA lamp indicates
data from the computer and the CON lamp indicates data being sent to the
computer. The DCD and PTT lamps display normally. With the original EPROM
the lamps had no logical sequence, if they displayed at all.
All my MFJ1270B TNC's now use KISS only EPROMs, using an image from TAPR.
EVERY timing problem disappeared when the KISS only EPROM was installed,
and the status indicators do what they're supposed to do.
I believe the timing problem didn't apply when using the original EPROM in
native mode but it's so long (20 years) since I've used native mode that I
really can't recall.
The added advantage of KISS only is the TNC is always in KISS mode.
Cheers ... Ray
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