[time-nuts] Serial port server .. any interest in a write up on using ?

Pete Lancashire pete at petelancashire.com
Tue May 22 22:37:41 UTC 2012


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_palmer at sasktel.net> 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 delay or variation in the delay?
>
> Ed
>
>
>
> On 5/22/2012 12:51 PM, Pete Lancashire wrote:
>>
>> 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 requires the computer to be close. For me I have
>> two locations where my gizmo's are not near the PC. The other is at
>> times I want to be able to run Lady Heather or Trimble Studio from my
>> Laptop which maybe out on the porch while having a beer and operating
>> the BBQ :-)
>>
>> Group buy
>>
>> The model I've been using is still made but even the 1 port model is
>> over $100. The 4 port model shows up on the E quite often
>> and I've been able to get them for as little as $20. The 16 port model
>> was $5 at a local used PC store.
>>
>> Cards (Internal)
>>
>> For me pretty much the same as USB, and the other for me is the PC I
>> have on the bench has only 2 short length PCI slots.
>> One is taken up with a GPIB card an the other a data acquisitions
>> card. Another is I have two benches. With a network attached
>> setup I can access my serial stuff from either bench.
>>
>> This is my setup your mileage may very like in many setups.
>>
>> Also past experience has not been pleasant with these things. If your
>> 100% Microsoft and never update past XP you may be
>> OK
>>
>> Other makes, Lantronix, Cyclades, etc.
>>
>> Other then Cyclades 48 port servers, Digi is the only other vendor
>> I've worked work. Hence not disqualifying anyone else
>> just what I've used.
>>
>> Terminal servers are simple boxes.  You just Telnet to the port.
>>
>> Some are, some like the current generation Digi's go beyond that. For
>> example the software that makes a port on the
>> Digi look like a COM (uSoft) or TTY (*nix) port. They even do things
>> like create port tunnels, where a serial port on two
>> box 'look' like the same port. One thing I like with the ones I have
>> is you can for example set port 1 to emulate a COM
>> port, port 2 to respond as a telnet session, port3 to only use SSL so
>> you can safely use it over the Internet, etc. And if
>> you really careful, you can have multiple network sessions telnet for
>> example to one serial port. Something I've not
>> yet tried.
>>
>> Cost
>>
>> Pretty much how good you are at finding stuff, where you live, etc.
>>
>> My 16 port unit was $5, the most I've paid is something like $40 (1/3
>> of it shipping) for a 4 port models.
>>
>> I will be adding a wiki to my yet to be developed website and will
>> make a page on what I've implemented, I'd love
>> to see what others have done with different makes and models,
>> specially in emulating COM/TTY ports.
>>
>> Before that I'll write up a short summery for this weekend.
>>
>> -pete
>>
>>
>>
>> On Mon, May 21, 2012 at 7:55 PM, Pete Lancashire
>> <pete at petelancashire.com>  wrote:
>>>
>>> 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 take from 1 to 48 RS232 ports on one side and
>>> let you talk to them via an Ethernet interface. I so far have twelve
>>> RS232 ports in use.
>>>
>>> Now that the need for such devices has diminished, these terminal
>>> servers are showing up, sometimes for pennies.
>>>
>>> One brand and model Digi's TS family of models I and have verified
>>> they work with Lady Heather and Trimble Studio on a Windows XP PC.
>>>
>>> Digi offers for free a program that makes each RS232 Port look like a
>>> COM port, and after configuring the terminal server, and this driver,
>>> you just just fire up Lady Heather pointing to the correct "COM Port".
>>>
>>> Other RS232 ports on the terminal server can either be COM ports, or
>>> one can be connected to via Telnet of for security SSH. For example I
>>> have an Odetics on one port
>>> and I just enter telnet ts4a (the DNS name I gave one of the terminal
>>> servers) 2003 (the IP port associated with the third RS232 port).
>>>
>>> So if this is of interest to anyone I'll go into more detail, models,
>>> setup etc.
>>>
>>> -pete
>
>
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