On Tue, 22 May 2012 17:28:47 -0700
Hal Murray hmur...@megapathdsl.net wrote:
Note that 4 samples are way off scale. The target machine is idle, but the
packets are going over a wifi link that has other traffic but is far from
overloaded. Yes, this is wifi rather than a simple ethernet
att...@kinali.ch said:
On an ethernet it looks quite different:
[snip lots of low jitter samples]
Network is a destkop - switch1 - switch2 - ntp box.
The switches are two Level1 Gbit smart switches. The desktop is a ~4y old
Xeon 2GHz system with a Gbit interface The ntp box is a AMD Geode
On Wed, 23 May 2012 01:54:20 -0700
Hal Murray hmur...@megapathdsl.net wrote:
There aren't noticable more jitter for moderate (1-2 MByte/s) traffic.
(Probably visible if i would do a statistical analysis...but..)
1-2 megabytes/sec is 8-16 megabits/sec. You won't get into serious troubles
server .. any interest in a write up on
using ?
On Wed, 23 May 2012 01:54:20 -0700
Hal Murray hmur...@megapathdsl.net wrote:
There aren't noticable more jitter for moderate (1-2 MByte/s) traffic.
(Probably visible if i would do a statistical analysis...but..)
1-2 megabytes/sec is 8-16 megabits
On Wed, May 23, 2012 at 9:08 AM, Bob Camp li...@rtty.us wrote:
Hi
If the timing involved is NTP, I'm not so sure that a normal home lan with
gigabit switches would be a problem. You can indeed saturate the poor thing.
Unless you have a very unusual system, it is unlikely you will saturate it
On Wed, May 23, 2012 at 12:13 PM, Chris Albertson
albertson.ch...@gmail.com wrote:
On Wed, May 23, 2012 at 9:08 AM, Bob Camp li...@rtty.us wrote:
Hi
If the timing involved is NTP, I'm not so sure that a normal home lan with
gigabit switches would be a problem.
One thing I forgot to add.
things a
bit.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Chris Albertson
Sent: Wednesday, May 23, 2012 3:13 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Serial port server .. any interest
On Wed, May 23, 2012 at 2:02 PM, Bob Camp li...@rtty.us wrote:
Hi
What ever degradation the serial stream sees on the LAN, the resulting NTP
output will see once it's on the same LAN. It's unlikely you will see more
than a 2:1 net degradation no matter what is going on. The flywheel in the
Hi
Ok, to be 1000: 1, you would take the 0.2 to 0.5 ms that you see on the LAN and
take it up to 200 to 500ms. That's *way* worse than anything I have ever seen
for a serial server over a LAN.
Bob
On May 23, 2012, at 5:15 PM, Chris Albertson wrote:
On Wed, May 23, 2012 at 2:02 PM, Bob Camp
On Wed, May 23, 2012 at 2:59 PM, Bob Camp li...@rtty.us wrote:
Hi
Ok, to be 1000: 1, you would take the 0.2 to 0.5 ms that you see on the LAN
and take it up to 200 to 500ms. That's *way* worse than anything I have ever
seen for a serial server over a LAN.
Yes, 200 ms would be insanely
Hi
Ok, at least now we are down to some numbers. Ever taken a look at NTP on a
Windows box running serial? It's not anywhere near a microsecond….
Bob
On May 23, 2012, at 6:47 PM, Chris Albertson wrote:
On Wed, May 23, 2012 at 2:59 PM, Bob Camp li...@rtty.us wrote:
Hi
Ok, to be 1000: 1,
As a FYI, the 6 port card I use is based on the4 Netmos NM9845CV. There
are a few vendors peddling serial cards using this chipset and part
number. Mine is from Best Connectivity (SD-PIO9845-6S). The card is
windows and linux capable.
___
time-nuts
On 05/22/2012 07:08 AM, Don Latham wrote:
I'm also interested. Maybe a group buy?
For strange reason I seem to see the same issue.
Cheers,
Magnus
Don
Jerry Mulchin
Ditto for me..
Jerry
At 08:16 PM 5/21/2012, you wrote:
I would be interested in some more information. I've got
of precise time and frequency measurement
Subject: Re: [time-nuts] Serial port server .. any interest in a write up on
using ?
Ditto for me..
Jerry
At 08:16 PM 5/21/2012, you wrote:
I would be interested in some more information. I've got quite a few
RS232 devices as well and not nearly enough
Hi
I'm interested as well. The USB gizmos are fine for close stuff. They aren't
quite so nice for gizmos in the attic when the computer is in the basement…
Bob
On May 21, 2012, at 10:55 PM, Pete Lancashire wrote:
Like many time-nuts I have quite a few devices that communicate to the
outside
Terminal servers are simple boxes. You just Telnet to the port. Not
much you need to know to use one. But the question is Where to buy
one cheap? Is someone on eBay or the like trying to unload a bunch
of these?
On Tue, May 22, 2012 at 4:26 AM, Bob Camp li...@rtty.us wrote:
Hi
I'm
I buy them on ebay. Usually $30+SH for 32 ports. 64 port units are harder
to find as are self booting units. (Most xylogics boot from the network,
which is easy enough to make work)
On Tue, May 22, 2012 at 11:46 AM, Chris Albertson albertson.ch...@gmail.com
wrote:
Terminal servers are
Some comments
The make and model I'm using is
Digi www.digi.com
http://www.digi.com/products/serialservers/portserverts#overview
I've used the 1, 4 and 16 port. The 1 and 4 are the same design.
USB
There are USB serial port servers, I have one that is 4 ports. But
like anything USB it
BB sent me an email today advertising optically isolated USB to
serial but the price awfully high for personal use:
http://www.bb-elec.com/product_multi_family.asp?MultiFamilyId=133Trail=45TrailType=Main
I have yet to be happy with any USB to serial conversion in legacy
applications. They
I've played with a Lantronix single port server and a Digi 16 port
server with no problems for simple COM port emulation. But I wonder if
they would work well with an NTP server. Has anyone tested that? Is
the network delay a problem due to either amount of delay or variation
in the delay?
ed_pal...@sasktel.net said:
I've played with a Lantronix single port server and a Digi 16 port server
with no problems for simple COM port emulation. But I wonder if they would
work well with an NTP server. Has anyone tested that? Is the network
delay a problem due to either amount of
Hi
I'd bet at least a cold order of french fries that you would be below 1 ms on a
modern home wired LAN. Certainly everything I ping locally is sub 1 ms unless
wireless is involved.
Bob
On May 22, 2012, at 4:44 PM, Hal Murray wrote:
ed_pal...@sasktel.net said:
I've played with a
I've never though about using one to distribute the 1PPS for NTP. Its
a pity there isn't enough umph inside one of these
little Linux boxes to implement NTP.
-pete
On Tue, May 22, 2012 at 12:39 PM, Ed Palmer ed_pal...@sasktel.net wrote:
I've played with a Lantronix single port server and a
On Tue, May 22, 2012 at 3:37 PM, Pete Lancashire
p...@petelancashire.com wrote:
I've never though about using one to distribute the 1PPS for NTP. Its
a pity there isn't enough umph inside one of these
little Linux boxes to implement NTP.
How little is the linux box? NTP runs fine on my 1.8Ghz
On 5/22/2012 3:39 PM, Ed Palmer wrote:
I've played with a Lantronix single port server and a Digi 16 port
server with no problems for simple COM port emulation. But I wonder if
they would work well with an NTP server. Has anyone tested that? Is the
network delay a problem due to either amount of
li...@rtty.us said:
I'd bet at least a cold order of french fries that you would be below 1 ms
on a modern home wired LAN. Certainly everything I ping locally is sub 1 ms
unless wireless is involved.
The delay doesn't matter much. You can correct for it. I can measure sub ms
even over a
On 05/22/2012 06:37 PM, Pete Lancashire wrote:
I've never though about using one to distribute the 1PPS for NTP. Its
a pity there isn't enough umph inside one of these
little Linux boxes to implement NTP.
Don't get too excited because this is many months out, but I'm working
towards designing
I've played with a Lantronix single port server and a Digi 16 port
server with no problems for simple COM port emulation. But I wonder if
they would work well with an NTP server. Has anyone tested that? Is
the network delay a problem due to either amount of delay or variation
in the delay?
Like many time-nuts I have quite a few devices that communicate to the
outside world with a serial port. And like many I have more then one.
In a past life I use to have to connect to sometimes a 100 RS232 in
one location. A popular device is called a terminal server or
concentrator. They would
I would be interested in some more information. I've got quite a few RS232
devices as well and not nearly enough ports even if I used all my computers.
Alan
On Mon, May 21, 2012 at 8:55 PM, Pete Lancashire p...@petelancashire.comwrote:
Like many time-nuts I have quite a few devices that
Ditto for me..
Jerry
At 08:16 PM 5/21/2012, you wrote:
I would be interested in some more information. I've got quite a few RS232
devices as well and not nearly enough ports even if I used all my computers.
Alan
On Mon, May 21, 2012 at 8:55 PM, Pete Lancashire
In message 20120522035119.lqwt4155.fed1rmfepo102.cox@fed1rmimpo305.cox.net
These days multiport USB-serial converters is a relevant low-cost
alternative to port-servers, but there are some features of
port-servers which don't seem to migrate over there, most notably
optically isolated ports.
I'm also interested. Maybe a group buy?
Don
Jerry Mulchin
Ditto for me..
Jerry
At 08:16 PM 5/21/2012, you wrote:
I would be interested in some more information. I've got quite a few
RS232
devices as well and not nearly enough ports even if I used all my
computers.
Alan
On Mon, May
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