IC-705 digital modes

Icom IC-705 Interface circuit for digital modes

IC-705 digital modes . The transceiver has a mode key for RTTY. You can use a PC and an application software to operate RTTY using a USB cable. See the interface circuit diagram below for details.

Refer to the software application’s instruction manual for setup details.

(Icom does not guarantee the performance of the application software, PC, network device, or network settings.)

When using the microUSB port



• To operate RTTY through your PC’s USB port, set the following item. menu SET > Connectors > USB SEND/Keying



System requirements

The following hardware and software are required:

  • PC
  • Microsoft Windows 10 (32/64 bit)
  • Microsoft Windows 8.1 (32/64 bit)* *Except for the “RT” version.
  • A USB 1.1,2.0, or 3.0 port

Cable a USB cable


• Purchase the proper USB cable according to your PC’s USB port.

For the Type-A port: User supplied For the Type-C port: OPC-2418 (optional)

• Use a USB cable for data communication. You cannot set up the radio with a cable that is made for charging only.

• Depending on the length of a third-party USB cable, the radio may not work correctly, even if the PC recognizes it. Use a cable that is as short as possible.


Before the installation_

  • When installing the driver, confirm Windows has completed its startup, and then log in as the administrator.
  • Confirm no other application is running.

Before connecting to a PC_

• The USB driver does not support the automatic recognition system. NEVER connect the USB cable between the radio and the PC until AFTER the USB driver has been installed.

See “Installing the driver” on page 3 for details. Once the driver has been installed, a PC software can be used by just connecting the USB cable.

• Directly connect the radio and the PC. Icom is not responsible for improper operation when connecting them through a USB hub.

After the installation_

• Uninstalling the USB driver

You cannot uninstall the USB driver for individual device. After uninstalling the USB driver, none of the devices that require this driver can be recognized by the PC.

• When another radio is connected

A COM port number is automatically added after turning ON the device.


• Depending on your PC performance (OS, environment, and so on), the USB audio may be interrupted, or a control by the PC software may get delayed.

• If the CPU has a heavy load, the USB audio is easily interrupted.

• The settings of the installed audio player may be changed after connecting the radio to the PC.


•    NEVER connect the USB cable between the radio and the PC until the USB driver has been installed. Disconnect the cable, if connected, before starting the USB driver installation.

•    This USB driver does not support the automatic recognition system.

Download the USB driver

Download Installation Guide for Windows 10/8.1 USB3.0 Supported


When using the [SP] jack, [MIC] jack, and [SEND/ALC] jack

Interface circuit example for digital modes (User supplied)

icom ic-705 Interface circuit for digital modes

TIP: We recommend using the SEND terminal on the [SEND] jack to change receiving and transmitting. If you use the PTT terminal on the [MIC] jack, the data may be cut off.

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Microsoft and Windows are registered trademarks of Microsoft Corporation in the United States and/or other countries.

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