larry wrote in news:Xns9A35D2BBAFB1noonehomecom@
208.49.80.253:

By the way, Seatalk isn't rocket science. Connect Seatalk data wire
(Yellow) to an RS-232C data in pin (pin 3 on the 25pin/pin 2 on the 9
pin) and hook Seatalk ground to computer data ground pin (7 on the 25, 5
on the 9). (I use little mini clips and made a snooping test cable.)
Boot good old Hyperterm. Save you a dumb terminal ASCII.ht connection
to make it easier to come back. Mine's on my laptop. Plug Seatalk
Hyperterm and look at the data, yourself, as it streams by. At some
point, after it has filled the buffer, pull the plug and look down
through the data for noise and crazy bits. Seatalk isn't encrypted...

If I'm correctly reading the technical description of the electrical
interface at http://www.thomas-knauf.de/rap/seatalk1.htm , I don't believe
that you can simply connect SeaTalk to an RS232 port and read the data
correctly. According to it, the voltages have to be inverted.

-- Geoff
www.GeoffSchultz.org

larry wrote in news:Xns9A35D2BBAFB1noonehomecom@
208.49.80.253:

By the way, Seatalk isn't rocket science. Connect Seatalk data wire
(Yellow) to an RS-232C data in pin (pin 3 on the 25pin/pin 2 on the 9
pin) and hook Seatalk ground to computer data ground pin (7 on the
25, 5 on the 9). (I use little mini clips and made a snooping test
cable.) Boot good old Hyperterm. Save you a dumb terminal ASCII.ht
connection to make it easier to come back. Mine's on my laptop.
Plug Seatalk Hyperterm and look at the data, yourself, as it streams
by. At some point, after it has filled the buffer, pull the plug and
look down through the data for noise and crazy bits. Seatalk isn't
encrypted...


To further correct Larry's statement, SeaTalk is encrypted in the sense
that it's a binary protocol. Datagrams are between 3 and 18 bytes in
length and are totally binary (the messages don't contain any ASCII
characters like you'd see in a NMEA sentence). Thus Hyperterm won't do you
any good unless a version that display hex bytes and knows how/when to
terminate a datagram.

-- Geoff
www.GeoffSchultz.org

Geoff Schultz wrote:

larry wrote in news:Xns9A35D2BBAFB1noonehomecom@
208.49.80.253:

By the way, Seatalk isn't rocket science. Connect Seatalk data wire
(Yellow) to an RS-232C data in pin (pin 3 on the 25pin/pin 2 on the 9
pin) and hook Seatalk ground to computer data ground pin (7 on the
25, 5 on the 9). (I use little mini clips and made a snooping test
cable.) Boot good old Hyperterm. Save you a dumb terminal ASCII.ht
connection to make it easier to come back. Mine's on my laptop.
Plug Seatalk Hyperterm and look at the data, yourself, as it streams
by. At some point, after it has filled the buffer, pull the plug and
look down through the data for noise and crazy bits. Seatalk isn't
encrypted...



To further correct Larry's statement, SeaTalk is encrypted in the sense
that it's a binary protocol. Datagrams are between 3 and 18 bytes in
length and are totally binary (the messages don't contain any ASCII
characters like you'd see in a NMEA sentence). Thus Hyperterm won't do you
any good unless a version that display hex bytes and knows how/when to
terminate a datagram.

-- Geoff
www.GeoffSchultz.org
I've built that interface circuit and it does work. Hyperterm
definately wont do the job. Larry must be confusing Seatalk with NMEA.

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL:
'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed,
All varnished hot moulded wooden racing dinghy.

On Thu, 31 Jan 2008 23:25:56 +0000, Ian Malcolm
wrote:

I've built that interface circuit and it does work. Hyperterm
definately wont do the job. Larry must be confusing Seatalk with NMEA.

Or he's got a Seatalk to NMEA converter somewhere.

http://www.landfallnav.com/ee85001.html

http://brookhouseonline.com/seatalk.htm

http://www.tklinux.de/seatalkBoard.html

Wayne.B wrote in
:

I've built that interface circuit and it does work. Hyperterm
definately wont do the job. Larry must be confusing Seatalk with NMEA.



No, you can see the streams of Seatalk with hyperterm....

If there is NOISE OR RF INTERFERENCE OR SOME SEATALK GOING CRAZY Hyperterm
will fill with graphic gibberish! You don't have to decode the Seatalk to
see the crap in there with it....

Larry, I'd like to discuss some of these topics via email -
can you please contact me at google atsign cognisense dot com?

Thanks, Keith

wrote in news:4237979d-40d7-4438-8874-7b45510d5828
@i29g2000prf.googlegroups.com:

can you please contact me at google atsign cognisense dot com?



Sure, but you're too late to hide the address because it shows up in your
message header. You might want to change that to a fake one to get it away
from the spambots.

I'll email you...

Larry wrote in
:

Wayne.B wrote in
:

I've built that interface circuit and it does work. Hyperterm
definately wont do the job. Larry must be confusing Seatalk with
NMEA.



No, you can see the streams of Seatalk with hyperterm....

If there is NOISE OR RF INTERFERENCE OR SOME SEATALK GOING CRAZY
Hyperterm will fill with graphic gibberish! You don't have to decode
the Seatalk to see the crap in there with it....

Wrong. It's a binary protocol and the signal levels are inverted from
RS232. There no ASCII characters involved in it. Read the document that I
posted the link to in rec.boats.electronics. If there's anything readable,
it's only by pure chance.

-- Geoff
www.GeoffSchultz.org