Re: [44net] hardware vs. software

"John D. Hays" <john@...>


I apologize if my reply wasn't what you expected.  The team has many tasks to complete before release of the UDR56k-4.  I answered with one, efficient, approach -- but it is not the only one.

You wrote:
"For example, assume I have four JNOS systems that are currently connected to
each other on a single subnet using a single 440 frequency.  They talk to
each other using IP over AX.25. I would definitely like to increase the
speed.  But it's not clear to me how I would deploy the UDR56K-4 to replace
the existing 440 radios/TNCs.  What protocol would it run, at what speed?
What would the IP network diagram look like?"

You could continue to do that using the UDR56k-4.  My supposition was that the equipment you currently use is not capable of the speeds available to the UDR56k-4.  If you are going to be replacing the TNCs and 440 radios with a UDR56k-4, then its possible to consider moving the JNOS service right into the radio, saving power and space, which is what I was describing -- however, you don't have to use it in that manner.  (See below)

On Sun, Jul 7, 2013 at 10:20 PM, Michael E. Fox - N6MEF <n6mef@...> wrote:
(Please trim inclusions from previous messages)
Thanks John,

But that wasn't my question.  If you re-read my question, you'll see that
the JNOS machines, network, radios, TNCs, etc. already exist.

The question was how to deploy the UDR56K-4 in a 56K bridge configuration on
a shared subnet to replace the existing 440 radios and TNCs.  For example,
some other technologies, like Icom's ID-1, only operate in a point-to-point
configuration (as far as I know).  That's why I asked about the shared
subnet.  Also, merely speeding up AX.25 to 56kbps isn't going to work unless
forward error correction is added.  Hence, part of my question was about
what protocol would be used.

While it was not mentioned in your earlier question, if you wish to run in an bridge manner, you have two options (and possibly a third):
  • Use IP over AX.25
  • Use Ethernet over D-STAR DD Mode 
(in the future there may be a lower overhead protocol).

56kbps (and above) AX.25 can operate without FEC.  It is a matter of path loss and modem BER.  Our modems are designed to minimize BER and one may find that FEC is not required for a given network.
On the other hand, adding a protocol agnostic FEC in the modem is a possibility, exchanging raw bit rate for data correction.  We are interested in this capability and will be looking at use cases for it.

At initial release, we will be delivering those capabilities listed on our information sheet at 

Since this device is flexible by design, new capabilities can be added at any time, either by us or other developers.  We believe this is a good investment value for our prospective customers.

Everything I've read so far, including your answer below, indicates to me
that the UDR56K-4 is really an experimenter's platform, and the end solution
is left to the user to figure out.  In other words, you're providing a linux
hardware platform with an integrated 440 radio.  That's cool.  But if the
solution I need is a 56K bridge, it sounds like it's up to me to find a
protocol with FEC that is allowed by the FCC, then find the source code,
compile it, test it, then somehow connect that to an IP routing or bridging
configuration in linux.  Am I interpreting the situation correctly?

We will be providing pre-provisioned applications for the UDR56k-4, some of those will be focused on EmComm data users, some on positional awareness users (e.g. APRS), and some on Digital Voice users.  For those applications, its configure and run.

We will also be providing application notes, e.g. "solution 'oriented' documentation" as the product is released.  This will include "bridging" solutions.

Unfortunately, we cannot engineer each user's unique application or solution.  We will provide information that will help various teams and individuals to engineer their own solution.

The intent of this mailing list "UniversalDigitalRadio" is a place to exchange that type of information between users with input from our team.

Right now our team is most focused on delivering a quality product with multiple capabilities.


-----Original Message-----
[] On Behalf

I don't have time right now to test, but JNOS2 compiles from source on the
UDR56k-4 as does jnosinstaller.  The installer configures the program just

Barring any unforeseen issues, you should be able to run JNOS directly on
the radio.  If you have TNCs servicing local LANs (e.g. 2 meters, 220, ...),
you can put USB-to-Serial interfaces on the UDR56k-4 and attach the TNCs
with their current radios. No other computer would be required.  We have
tested TNCs attached in this manner on other applications for over a year
(daily).  The four UDR56k-4s would form your backbone radios.  AX.25 drivers
are already in place to drive the UDR56k-4 at any supported speed including
9600-baud to over 56k baud (with some steps in between).  You would use a
CIDR of /29 if these were the only radios on your backbone LAN.

This is an open architure/system so bring your favorite applications (Linux
source or Linux ARMEL binaries) to the radio.  If your application is more
appropriate to run on another computer, use the UDR56k-4 as a relay device,
using an IP interface (wired or wireless).

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