[time-nuts] Serial-Ethernet

Joseph Gray jgray at zianet.com
Tue Mar 15 21:05:19 EDT 2016


On Thu, Feb 25, 2016 at 1:38 AM, Tom Van Baak <tvb at leapsecond.com> wrote:
>
> And, if you have a couple of 422 devices, consider the economics of a 4-port unit like:
>
> http://www.ebay.com/itm/301881123530

As promised, I am reporting on the USR-N540, 4-serial-port to Ethernet
box that Tom linked to. I had originally found it for less, but after
ordering, the seller emailed back to tell me he had no more at that
price. In any event, after about three weeks from China, my unit
arrived today. I haven't had any long term experience with this thing,
so hopefully it will continue to work.

It was very well packed in a small box with hard foam. Included are
the converter box, wall wart (switcher), 2-pin screw terminal power
adapter, serial cable, Ethernet cable and four DE-9 to 4-pin screw
terminal adapters (for RS-422, RS-485). No documentation and no
software. The box is made from steel and seems substantial. The power
input is labeled "DC: 9-24V".

I downloaded manuals and software from here:
http://www.usriot.com/p/4-serial-port-to-ethernet-converter/

One annoying thing is that the box is setup with a static IP, instead
of DHCP. The default IP of 192.168.0.7 is printed on the bottom, as
well as in the manual. The MAC address is not printed on the bottom.
The manual also lists the default login credentials.

I initially only configured Port 1 in the web interface, to test with
my HP Z3801A (RS-232, 19200, 7, odd, 1). I then installed the Virtual
Serial Port software. This seems to be a licensed version of the
Eltima software http://www.eltima.com/products/vspdxp/. Or, perhaps
the Eltimat software is licensed from USR IOT?

In the software, you can click on the "Smart VCOM" button and all four
ports will be assigned for you, using the first available port numbers
on your PC. I wanted a sequential range of 10-13, so I configured each
port individually, using the "Add COM" button. The interface box uses
TCP/IP ports of 23, 26, 29 and 32 by default, but these can be changed
in the web interface. Interestingly, the MAC address can also be
changed.

The web interface is very well laid out and logical, as is the Virtual
Serial Port software. I have been connected to the Z3801A for almost
half an hour and things seem to be working just fine. I'll update if I
encounter any problems later. I will have to try the RS-422 with my
Lucent GPSDO.

All in all, I am pleased with this converter box. At $20 per port, it
seems like a good deal for a new item. I know that others are using
surplus terminal servers that they bought for less.

Approximate dimensions: 8.5" (including mounting ears) x 4.75" x 1.2"

Joe Gray
W5JG


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