Digital Master 780 DM780 CW Send CW Interface – How To

I have a video out on this, but I have more information and pictures in the article. How does a good CW interface cable work with DM780? Great and it just plugs into the CW jack on the back of the radio. I have been using the same CW interface for many years. It was used with an old Kenwood and I use it with the Icom transceivers I have now. Digital Master 780 sends good CW using this type of interface, but if you want to go all out try a Winkeyer.

dm780 cw interface

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See my previous article on DM780 CW Decode.

DM780 CW Interface

There are at least a few ways we can send CW with DM780 and I have tried them all over the years with the exception of a Winkeyer or devices like that. CW (SSB) is not recommended, at least in the US it isn’t. CW (KY CMD) works okay, but I always seem to run into problems eventually with it. It doesn’t matter what radio I am using. I find it works 👌  for short messages.

Using CW selected in DM780 and a CW interface cable is good solution. The cable I have I got many years ago. I think it is a W1GEE cable, it is essentially this one:
W1GEE CW Interface.

I have a different one (USB to 1/4″ plug) on order. It is less expensive, but may not work as well. I am holding my thoughts on it. I’ll update this article later.

UPDATE 4/6/2019: Received my new cw interface and it is working FB. Check the RTS CW keying in DM780.

CW Interface and Icom 7300

With the Icom 7300 we only have one CW jack on the back of the radio. It’s a 1/4″ jack, but thank goodness we can use a splitter, You don’t have to, but I like it in line. This way I can have a key and the PC hooked up at the same time.

Icom 7300 Keyer Settings

Put the Icom 7300 into CW mode. Control CW pitch in the radio, but control CW speed in DM780. Have a look at the video below.

Keyer type: Straight key. See the video on setting that up in the Icom 7300.

Digital Master 780 DM780 CW

Go to Options. I am using HRD for PPT. On the CW tab I am using the Com port for my CW interface and then a few other minor tweakes so the CW sound good. See below.

I have not been using the Breakin option in the toolbar.

My toolbar


Here’s a good video showing the CW interface, Y-cable or splitter and CW straight key. There’s also a demonstration on how it can be used.

Thank you

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See my previous article on DM780 CW Decode

N3FJP’s excellent CW interface page

My CW Interface

Y-Cable or Splitter


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I'm an Amateur Radio enthusiast. I love the hobby and experimenting with radios, antennas and software. On my YouTube channel I upload videos on the Icom 7300 and Icom 7610 along with Ham radio software programs. I hope to inspire people to try new things in Amateur Radio.

6 Responses

  1. blank Colyn says:

    I use a 7300 as well as a 7610 and I enjoy reading all the information about the sets very useful.
    The one comment I have between the two set is concerning the preamp. 7300 Preamp 1 and 2 work on all bands but with the 7610 only preamp 1 works on all bands and 2 works only on the 10m and 6m bands.

  2. blank K0PIR says:

    Hi Colyn,

    Nice to hear from you and thank you for commenting here. That’s similar to what the manual says about the preamps. On the 7300:

    P.AMP1: Wide dynamic range preamplifier.
    It is most effective for the HF low bands.
    P.AMP2: High-gain preamplifier.
    It is most effective for the higher bands.

    Icom includes a little more detail in the manual for the 7610. I don’t know why they would be so different though. I haven’t tried between the two, but I will now.

    I normally don’t use the P.AMPs, but this time I was trying it with CW to see if it helped with raising the CW signal so the software could decode better. P.AMP1 may help on some weaker signals.

    Thanks for the information and your input. I appreciate it.

    Best 73,
    Rich, K0PIR

  3. blank Dave Borchard says:

    I think you are using the W1GEE DB9 to 1/4″ CW cable. I ordered that cable from the N3FJP CW web page. You also had a link to a USB to 1/4″ CW cable. Does that also work to key the CW on a 7610?

    • blank K0PIR says:

      Hi Dave,
      Nice to hear from you and thank you for commenting here.

      Although I have not tried it on the 7610, I see no reason why it wouldn’t. The USB to 1/4″ does work very good on the 7300. I made multiple QSO’s with it using DM780 and I couldn’t tell a difference between it and the other CW interface. I’ll be using it when I am mobile and portable.

      Thank you again Dave and best 73!

      Rich, K0PIR

      • blank John Zempel says:

        Just tried setting up my IC7300 with DM780 to use transmit CW. I plug in the USB to 1/4 in. Interface cable, rather than a com port it shows up as “USB PnP Sound Device” in device manager. And DM780 dosen’t key the radio to transmit. Any suggestions? Thank you. John Zempel KG4OLG

  4. blank K0PIR says:

    Hi John,

    I have one of these, USB CW Interface.
    It shows up under Ports (COM & LPT) as USB-SERIAL CH340.
    Is your computer software (OS) up to date?
    Try unplugging it and plugging it back into another of your computers USB ports.
    USB CW Interface

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