[time-nuts] Advice on NTP server needed

Alan Melia alan.melia at btinternet.com
Mon Jun 13 22:25:54 UTC 2011

This is raising an interesting point, only vaguely relevant, but we have
testing some software for amateur radio astronomy purposes that controls
intruments over serial lines RS-232 or RS-485. Whilst many application run
with out problems for days on internal serial cards, we seem unable to find
any USB to serial converter that performs anywhere near as well.on our
loopback tests. Many of the fail rates suggest that slower speeds give a
longer period between errors, but with one well-known converter we could not
run at all at 57.6kB. This may not be too much of a problem with GPS control
program speeds but it would seem there are few totally reliable products. It
may be much more serious for NTP operations.

Of the USB converters the best seemed to use the FTDI chip and driver, but
these have shown fails suggesting the problem is deeper inside the PC. All
problems have been on the PC reception leg, causing corruption, and often
what seemed like a driver disconnection so the "serial port" became
disconnected from the application, and required the app restarting.

Alan G3NYK

----- Original Message ----- 
From: "David VanHorn" <D.VanHorn at elec-solutions.com>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Monday, June 13, 2011 10:46 PM
Subject: Re: [time-nuts] Advice on NTP server needed

> ________________________________________
> Unfortunately, my D525 mobo doesn't have a serial port and my symetricom
> doesn't like the usb converter. One of these days somebody is going to
> make a usb coverter that really looks like a serial port. I'm probably
> going to buy a serial card for the box if all else fails.
> The best serial port boxes I have found, are Edgeports.  They are
available in 1/2/4/8/16 port versions, and I've picked up the 8 port
versions for $50 on ebay.
> Dead solid, and reliable.  I haven't hit anything that wouldn't work with
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