Cable for ICOM IC-281H

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The transceiver is equipped with an accessory data port which is always a preferred option compared to interface via mic/speaker connections:

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The 9600 baud Digirig audio cable will look like this:

DATA 2.5mm TRRS tip (Data input) → 3.5mm TRRS ring 1 (RIG_AFIN)
DATA 2.5mm TRRS ring (PTT) → 3.5mm TRRS ring 2 (RIG_PTT)
DATA 2.5mm TRRS sleeve (GND) → 3.5mm TRRS sleeve (GND)

SP 3.5mm TRRS ring (GND) → No Connection
SP 3.5mm TRRS ring (GND) → 3.5mm TRRS tip (RIG_AFOUT)
SP 3.5mm TRRS sleeve (GND) → 3.5mm TRRS sleeve (GND)

9600 baud audio path is also suitable for standard 1200 baud based digital modes.

NOTE for 9600 bps operation:
• If the transceiver does not transmit (the transmit indicator flashes or does not illuminate), the input level may be higher.
• If the re-try function is activated frequently, the input level may be lower.

Operation:

  1. Connect a TNC to the transceiver’s [SP] and [DATA] jacks.
  2. Set the operating frequency. Push and hold [LOW-DATA] for 1 sec. to select data mode.
    • “DATA” appears.
    • The microphone signals are cut from the modulation circuit while in data mode.
  3. Control the transceiver from a personal computer, etc.
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I have an IC281H, and would be interested in an interface cable. Is this in development, or would you recommend I make my own cable?

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There is not a lot of demand for IC-281H cables so at this time there is no plan to add this model to the lineup.

Please report your results if you decide to go ahead with the homebrew cable.

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I just got a DigiRig, and I have an old ICOM IC-281H. I have homebrewed my own cable. I decided to make a nice Schematic diagram, like the other DigiRig diagrams, for the cables in the store. While I was looking for one, I found that the ICOM RJ45 cable works for a 1200-baud interface. I went ahead and made a couple of cables of my own, and wanted to share the diagram.

DigiRig 1200 Baud IC-281H
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If you want to take advantage of the built-in 9600-baud interface on the IC-281H, you will need a different cable; just swap the T wire with the R wire on the 3.5 mm plug.

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You might be able to make a switchable cable to swap the lines, but given the cost of the pieces, I think it’s cheap enough to just make a second cable. Additionally, I am planning on leaving it plugged in, so I don’t need to change modes, it will be one or the other for me.

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