I have an idea to provide additional radio network connectivity to the Snohomish County DEM at Paine on 23cm, that would require one or two fixed 44.x.x.x IP addresses at the DEM, and one at my house (separate from my MikroTik radio), that would be accessible via the present 44.24.240.x connection to Paine (and perhaps any other 44.24.240.0/20 address).  Both involve the use of two (or more) Icom ID-1 radios in D-Star DD mode.

Background:  An Icom ID-1 in DD mode acts just like a piece of Ethernet cable (except that it is half-duplex and limited to a raw 128Kbps speed).  No IP address is (or can be) assigned to the device. Any Ethernet packet reaching the ID-1's Ethernet port (whatever the content) is simply encapsulated and transmitted if the radio is in DD-mode.  Similarly, any received data (properly encapsulated by another ID-1) is simply sent out the receiving radio's Ethernet port.  The only radio configuration possible is to select a 23cm frequency and set the radio into DD-mode.  Most of these actions can either be done by the radio's control head, or via a USB port "connected" to a Windows PC running Icom's control software for the ID-1.  This prior sentence is important in the following discussion.

As an aside, the transmission of an ID-1 can be addressed to and received by a D-Star DD-mode "repeater" module, routed via the D-Star network over the Internet to another such "repeater" module anywhere in the world, and retransmitted over the air to a receiving ID-1 radio.  This mechanism, while perhaps interesting, is not the subject of this eMail.  I only mention it so as to avoid confusion.

In scenario #1 for the ID-1 that already is installed at the Snohomish County DEM:
  1. The Ethernet port of the ID-1 is directly connected to a switch at the DEM that is on the 44.24.240.x network.  In this mode, any packets received over-the-air by the ID-1 are injected into the local 44.24.240.x network, and are routed in exactly the same manner as from any other device hard-wired to the 44.24.240.x network at the DEM.  Further, any Ethernet packets seen by the ID-1 (whether intended for radio transmission or not), would be transmitted by the ID-1.
  2. Another ID-1, located (say) at my house would be connected to a router, which would act as though it were directly connected to the 44.24.240.x network at the DEM.
I don't view the above scenario as a good idea.  For one thing, the indiscriminate transmissions from the DEM of unrelated 44.x.x.x packets doesn't seem like a good idea.  For another, there is no security.  So, that brings me to scenario #2:
  1. At the Snohomish County DEM, place a router (or bridge) between the ID-1 and the 44.24.240.x network.
  2. In this scenario, the ID-1 located at my house would also be connected to a router that acts as though it were directly connected to the 44.24.240.x (or any other) network at the DEM.

Now, here is the wrinkle (to both scenarios):  The ID-1 at the DEM is currently in VERY LOW utilization, being (as so far as we know) only able to contact my ID-1 (in either digital  data or voice mode), and the two 23cm D-Star K7LWH repeater modules (one voice, and presumably one data) in Bellevue.  Also, the ID-1 also supports normal FM voice mode, and is easily able to hit with one watt (from both the DEM and my house) the KB7CNN 23cm FM repeater on East Tiger Mountain.  So, it would be nice to use the DEM's ID-1 radio in different modes, as needed, and switch modes or frequencies REMOTELY as desired.  The solution to this the use of a Digi "Anywhere/5" (or "/2") Ethernet-to-USB box (I have several).  With the installation of Digi drivers on any Windows PC, these allow a PC anywhere in the world to connect over the Internet to a Digi box and have access to several remote USB devices (including any connected USB hubs).  In particular, the USB control port of an ID-1.  In fact, this is how I control my ID-1 at home:  this allows me to control the ID-1 from any Windows PC.

Hence the desire for a fixed 44.24.240.x IP address for the Digi box at the DEM, allowing REMOTE control and configuration of the ID-1 when the Internet is not available.  While the Digi box can be connected to any network at the DEM, it seems most productive to connect it to the 44.24.240.x network there, allowing remote configuration and control of the ID-1 in an Internet outage (this can be disabled by unplugging the ID-1's USB port).  Unfortunately, the Digi USB boxes are only usable from Windows systems (Digi's remote SERIAL (RS-232) port boxes are supported not only on Windows from 98 on, but on most variants of Linux ...).

Yes, this provides a much slower connection to the DEM than the MikroTik radios, but doesn't have quite the strict line-of-sight issues that 5cm does, and thus permits some mobile access.

To Scott Hokaker:

I am willing to provide a Digi "Anywhere/5" box on permanent loan (or perhaps donation) to this project.  I also have a couple of consumer-grade routers (Linksys BEFSR41, Netgear WGT624v2) that are similarly available, if they are suitable.

Comments welcome!

-- Dean