Easy Ethernet-to-Serial Interface

Build an inexpensive wired Ethernet-to-Serial interface.

New smartphone devices have a serious defect (at least in my view). They don't support the Bluetooth SPP stack (serial port). This pretty much takes Bluetooth devices such as CTR-BlueLync and the SparkFun Bluetooth modems out of the picture for radio control.

But all is not lost. All versions of CTR and the new iCTRcvr program support IP based connections to your radio. All you need to do is provide an IP-to-serial converter to get the data from your network to a serial port and back again.

CTR-Server offers one Ethernet-to-Serial solution. The drawback with this program is that your PC must be running for it work.

What's needed is a stand-alone Ethernet-to-Serial server that can connect your router directly to your radio without a computer in the middle. A quick Google search reveals that there are several ready to use serial port servers on the market ranging from USD$89 to well over USD$200. But then what's the fun of buying a commercial device when for around USD$30 you can buy a WIZ110SR Ethernet-to-Serial board from SparkFun.com and build your own?

Below is a pictorial of how I built mine (I actually have two of them, they are pretty handy to have around).

NOTE: I am not in any way connected to sparkfun.com or www.wiznet.co.kr (the manufacturer of the WIZ110SR), or Hammond Manufacturing. I just think this is a way cool way to connect to my radio!

You will need the following:

  • WIZ110SR Ethernet-to-Serial Gateway - see www.sparkfun.com (USD$29.95)

  • Hammond Manufacturing Enclosure, see www.digikey.com part number HM915-ND (USD$10.44)
    You can use any enclosure you want (or none at all if you're brave).

  • 5 VDC power supply, serial cable, and CAT5 cable (I'm sure you have several of these rattling around in your junk box).

The WIZ110SR fits neatly inside the component space in the Hammond box. A hole for the serial port was cut in the end blank supplied with the box and the partition between the component compartment and the battery compartment was cutout to allow the Ethernet and power connections to enter through the battery compartment.

Here's the serial port view. The two threaded studs attach the WIZ110SR's serial port to the front panel, keeping it secure. The foam on the Ethernet connector further cushions the board and keeps it from wobbling around in the box.

The Ethernet and power cables enter through the battery compartment.

Here's a shot of the Ethernet/Power end showing the slot I cut to allow cable entry.


Here's the completed unit. I built a short serial cable for the PCR-1000 with pins 7 & 8 shorted on the DB9M (radio end) so the radio stays on when I disconnect. Pins 2, 3, and 5 are connected straight through for the PCR-1000 (the gateway looks like a PC serial port, i.e. DTE). The connector on the IP-to-Serial adapter is a DB9F.

Finally, here's completed unit with the PCR-1000.

This unit can be used with any radio that you can control with RS-232. For a Yaesu with the 8-pin miniDIN interface you'll need a CT-62 adapter, for Icoms with the C-IV interface you'll need a C-IV adapter, and for older Kenwood radios you'll need a IC-232 adapter.

NOTE: It is highly recommended that you build a custom cable if you plan on using this (or any RS-232 port) with the Elecraft K2 radio because of non-standard power/voltage connections present on the K2's serial port. Refer to their documentation!

Using the Ethernet-to-Serial Gateway

One of the nice features of the WIZ110SR is that it can be fully configured via the Ethernet port. Through this port you can set it's TCP/IP address and change the serial port properties. Other Ethernet-to-Serial gateways require you to configure them through their serial port.

You will use the supplied WIZ110SR Configuration Tool to configure the gateway. Power up the gateway with a 5 VDC power supply, connect it to your LAN and use the Search feature in the configuration tool to locate the gateway on your LAN.

Once you have this screen up you can edit the TCP/IP addresses, ports, and subnet for the Ethernet side. You'll connect to the Local IP address and Local IP Port when you connect using CTR software. The Gateway and Server IP addresses and port should be set if you plan on experimenting with them. Set the other setting as shown above.

Next, click on the Serial tab to set the serial properties to match your radio.

Finally, click on the Option tab and enter the following settings. These allow the gateway to operate with CTR software. You may need to adjust the Time property if you find you have problems maintaining a reliable connection over the Internet. These settings worked well on my LAN/Wifi network.

CTR radio control software directly supports TCP/IP connections. Just enter the Local IP address you entered in the Network tab as the TCP/IP Host Address in the Comm menu and the Local IP Port number from the Network tab as the TCP/IP Host Port, again in the Comm menu. In iCTRcvr, just click the Wifi icon next to the meter and enter your IP address and port.

As with all aspects of ham radio, experiment a little, get your hands dirty a little, learn a little, and have FUN!


Click here to download the latest user manual for CTR products.

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