"Larry W4CSC" wrote in message
...

Ethernet requires a router and ethernet hubs to
connect devices.

No it does not. Ethernet over 10base-T (cat5 cable) requires a hub and a
cable to every device. The now almost obsolete thin ether net (10base-2, or
coax) would allow you to run a cable from device to device, using BNC T's at
every device.

USB, on the other hand, WOULD let the GPS talk directly to the chart
plotter.

No. USB works with one master and many slaves. Generally the computer is the
master an all other devices are slave. To make a GPS master, it would
require different USB hardware inside the GPS and quite some computing power
to behave as a USB master.

But, USB wouldn't work well in a broadcast situation because
it only allows two devices to talk to each other.

USB is master-slave. So only the master can initiate communications to a
slave, by asking if the slave has something to say. Slave can NEVER talk to
eachother.

NMEA2000 (CAN based) isn't all that bad, the problem is that it is not an
open protocol and you have to pay heavily to get your first NMEA2000
compliant device on the market. Buying the standard documents, test suite,
manufacturet and product ID for the first product costs about $10,000!

Like I have mentioned before, NMEA-0183 could well be upgraded to higher
speeds and a bidirectional bus (RS-485). Something like combining NMEA
(point to point, but RS-422) and Seatalk (broadcast but single wire) into
high speed RS-485. Still cheap to implement.

Wireless, either 802.11-something ethernet or Bluetooth is the best
answer. Wireless uses no wireway space. Instruments can be placed
anywhere you can get DC to them.

If you can get DC to an instrument, you can also get a twisted wire to that
instrument.

Wireless is too unreliable. When I walk away from my Bluetooth multiplexer
with my Palm in hand, I lose conact after one brick wall and 5 meters
distance. Even my WLAN stops at two concrete floors.

So imagine what happens in a metal hull.....

Meindert

On Sat, 31 Jan 2004 16:27:07 +0100, "Meindert Sprang"
wrote:

"Larry W4CSC" wrote in message
...

Ethernet requires a router and ethernet hubs to
connect devices.

No it does not. Ethernet over 10base-T (cat5 cable) requires a hub and a
cable to every device. The now almost obsolete thin ether net (10base-2, or
coax) would allow you to run a cable from device to device, using BNC T's at
every device.

The keyword is "obsolete". SOMEONE in an ethernet system has to be in
CONTROL, assigning IPs and controlling the movement of packets. It's
not just a broadcast medium. Again, we have the old problem of ONE
talker and a bunch of listeners, just like NMEA0183.

Of course, it will keep Meindert in work if we have extra boxes to
buy...(c;

USB, on the other hand, WOULD let the GPS talk directly to the chart
plotter.

No. USB works with one master and many slaves. Generally the computer is the
master an all other devices are slave. To make a GPS master, it would
require different USB hardware inside the GPS and quite some computing power
to behave as a USB master.

Same problem I point out with the router or hub scenario. Tons of
wiring to a central control point. Where will all the wires go in the
overloaded boat wireways? Who will act as the controller? Will I
have to buy a $2000 notebook to act as a "hub" for the USB? Not
practical, either financially or physically.

But, USB wouldn't work well in a broadcast situation because
it only allows two devices to talk to each other.

USB is master-slave. So only the master can initiate communications to a
slave, by asking if the slave has something to say. Slave can NEVER talk to
eachother.

Same as NMEA.....one talker many listeners. Same old problems.

NMEA2000 (CAN based) isn't all that bad, the problem is that it is not an
open protocol and you have to pay heavily to get your first NMEA2000
compliant device on the market. Buying the standard documents, test suite,
manufacturet and product ID for the first product costs about $10,000!

Like I have mentioned before, NMEA-0183 could well be upgraded to higher
speeds and a bidirectional bus (RS-485). Something like combining NMEA
(point to point, but RS-422) and Seatalk (broadcast but single wire) into
high speed RS-485. Still cheap to implement.

Wireless, either 802.11-something ethernet or Bluetooth is the best
answer. Wireless uses no wireway space. Instruments can be placed
anywhere you can get DC to them.

If you can get DC to an instrument, you can also get a twisted wire to that
instrument.

Wireless is too unreliable. When I walk away from my Bluetooth multiplexer
with my Palm in hand, I lose conact after one brick wall and 5 meters
distance. Even my WLAN stops at two concrete floors.

I have no problems with my Bluetooth connections at 20 ft. I don't
have any brick or concrete walls in the boat. They are conductive and
absorptive, unlike fiberglass and plastics used in boats. Maybe we'll
just use 802.11b?

So imagine what happens in a metal hull.....

Meindert


Notice my note that this is for PLEASURE YACHTS made of PLASTIC AND
FIBERGLASS. How many boaters in any marina have a steel hull? Here,
I'd say it's around 1%? less?



Larry W4CSC

No, no, Scotty! I said, "Beam me a wrench.", not a WENCH!
Kirk Out.....

"Larry W4CSC" wrote in message
...
The keyword is "obsolete". SOMEONE in an ethernet system has to be in
CONTROL, assigning IPs and controlling the movement of packets. It's
not just a broadcast medium. Again, we have the old problem of ONE
talker and a bunch of listeners, just like NMEA0183.

Again no. If all of the devices on an ethernet would only send out broadcast
packets, every device could have the same IP address. And the collision
mechanism present in every ethernet controller does the rest. So every
device is able to send data in the form of a broadcast (IP adress ends on
x.x.x.255) and every device receives that. All are equal peers. And for
low-bandwidth NMEA data this would be a perfectly feasable solution.

Of course, it will keep Meindert in work if we have extra boxes to
buy...(c;

Well, I could make a multiplexer with an ethernet connection, if you like.

Notice my note that this is for PLEASURE YACHTS made of PLASTIC AND
FIBERGLASS. How many boaters in any marina have a steel hull? Here,
I'd say it's around 1%? less?

Not every pleasure yacht is made from plastic. I have been in places where
95% of the boats were steel.

Meindert

Furuno is using Ethernet (they call it NavNet) and I understand NorthStar is
introducing Ethernet devices. And I know of a company that makes a
waterproof connector hub (of course it uses those impossible to find, so you
have to buy the cable from Furuno, connectors).
Doug K7ABX
"Meindert Sprang" wrote in message
...
"Larry W4CSC" wrote in message
...
The keyword is "obsolete". SOMEONE in an ethernet system has to be in
CONTROL, assigning IPs and controlling the movement of packets. It's
not just a broadcast medium. Again, we have the old problem of ONE
talker and a bunch of listeners, just like NMEA0183.

Again no. If all of the devices on an ethernet would only send out
broadcast
packets, every device could have the same IP address. And the collision
mechanism present in every ethernet controller does the rest. So every
device is able to send data in the form of a broadcast (IP adress ends on
x.x.x.255) and every device receives that. All are equal peers. And for
low-bandwidth NMEA data this would be a perfectly feasable solution.

Of course, it will keep Meindert in work if we have extra boxes to
buy...(c;

Well, I could make a multiplexer with an ethernet connection, if you like.

Notice my note that this is for PLEASURE YACHTS made of PLASTIC AND
FIBERGLASS. How many boaters in any marina have a steel hull? Here,
I'd say it's around 1%? less?

Not every pleasure yacht is made from plastic. I have been in places where
95% of the boats were steel.

Meindert

In article ,
(Larry W4CSC) wrote:

SOMEONE in an ethernet system has to be in
CONTROL, assigning IPs and controlling the movement of packets. It's
not just a broadcast medium. Again, we have the old problem of ONE
talker and a bunch of listeners, just like NMEA0183.

Well not really Larry, someone has to assign IP address's, but if one
does Static IP Assignments then you only have to do it once per device.
Ethernet doesn't have talkers and listners as such. ALL Devices are BOTH
and the protocol and timing decides who's turn it is to talk next, while
everyone else listens.

Bruce in alaska
--
add a 2 before @

How many network engineers are boat owners at your marina? I know of
2, here. The rest of them will be glad to let the DHCP server on the
router take care of their mundane networking details, allowing them to
simply turn on the new device hooked to the LAN and the router
autoconfigures it.

Boaters LOVE Plug 'n Pray.



On Sun, 01 Feb 2004 19:13:36 GMT, Bruce in Alaska
wrote:

In article ,
(Larry W4CSC) wrote:

SOMEONE in an ethernet system has to be in
CONTROL, assigning IPs and controlling the movement of packets. It's
not just a broadcast medium. Again, we have the old problem of ONE
talker and a bunch of listeners, just like NMEA0183.

Well not really Larry, someone has to assign IP address's, but if one
does Static IP Assignments then you only have to do it once per device.
Ethernet doesn't have talkers and listners as such. ALL Devices are BOTH
and the protocol and timing decides who's turn it is to talk next, while
everyone else listens.

Bruce in alaska
--
add a 2 before @


Larry W4CSC

No, no, Scotty! I said, "Beam me a wrench.", not a WENCH!
Kirk Out.....

"Larry W4CSC" wrote in message
...
How many network engineers are boat owners at your marina? I know of
2, here. The rest of them will be glad to let the DHCP server on the
router take care of their mundane networking details, allowing them to
simply turn on the new device hooked to the LAN and the router
autoconfigures it.

Like mentioned earlier: let all nodes send only broadcasts. That way, no
device on the net needs a unique IP address. Every device could be factory
programmed with the same IP address.

Meindert

Furuno uses TCP/IP according to their on-line FAQ, but the higher level
information is proprietary. They also don't use standard 10/100BaseT
connectors which aren't waterproof.

Question
Will I be able to connect my computer to the Navnet hub and
display NavNet information on the computer?
Answer
The Navnet system uses a TCP/IP computer protocol. This protocol is
a open architecture that allows for multiple ways of connecting the
NavNet system. The standard blue null cable(crossed input and output) or
10 Base hub are the normal configurations although other options have
been used. This allows the NavNet components to communicate together
using the existing, flexible and robust computer technology. However,
the protocol is only the transport mechanism, the actual information is
proprietary to Furuno. At this time Furuno has no software to translate
the information into a computer based program. The actual benefit of
such a program is suspect as it would prove difficult to map the
computer keyboard to conform to the NavNet controls. An additional
NavNet display is the optimal choice because it allows quick and
complete control of all NavNet functions and is waterproof.

See: http://www.pseaconcepts.com/

for a company which has a few items of interest.

A better way would be to asign "well known" IP address in the multicast
range to the diferent types of information. That way a listener could
subscribe only to those broadcasts that are of interest to it.

NMEA 0183 has one really good thing going for it. It is in human
readable ASCII which makes it a cinch to debug. ASCII is inefficient of
bandwidth at 4800 bps, however.

Joe Wood

Meindert Sprang wrote:

"Larry W4CSC" wrote in message
...

How many network engineers are boat owners at your marina? I know of
2, here. The rest of them will be glad to let the DHCP server on the
router take care of their mundane networking details, allowing them to
simply turn on the new device hooked to the LAN and the router
autoconfigures it.


Like mentioned earlier: let all nodes send only broadcasts. That way, no
device on the net needs a unique IP address. Every device could be factory
programmed with the same IP address.

Meindert