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Connection to the radio


Cables

The radio is connected to the computer using a level converter cable. The Links page of the website lists sources of ready-made cables that can be ordered over the Internet as well as several DIY circuit designs.

Cables that connect to a Serial port incorporate a voltage level converter to convert between the +/- 12V of RS232 to the +5V/0V of TTL voltage levels needed by the transceiver.  The cable also converts the 3 wire RS232 circuit (TX/RX/GND separate wires) to the 2 wire GND/TX+RX used by the radio. Do not attempt to directly connect the radio to a RS232 Serial port just by using adapter cables - a proper level converter circuit is essential.

Many recently manufactured laptop computers do not have a real serial port. If you have one of these laptops you will require a USB to Serial adapter to enable connection of the level converter cable. If you use a level converter that takes power from the Serial port (such as the CT-29B) you may have problems in providing sufficient power to the level converter circuit from the USB/Serial converter. See here for a test you can perform on the voltage level available at your serial port.

Alternatively, cables that connect directly to a USB port are also available.


The 4-way plug

The VX-3 requires a 4-way plug with a narrow neck that will permit it to fit into the recess around the socket. Tip is unused, ring 1 is data, ring 2 is unused, common is GND. This picture of the top of the radio shows the recess into which the plug must fit in order for the internal connectors to line up. The socket is the center of the radio.



The plug that the author uses is the Yaesu CT-91. It is designed for use with the VX-6, VX-7, VX-170 and other handhelds which have a water resistant seal around the socket but it also fits the VX-3, FT-60, VX-110 and VX-150. The CT-91 has 2 fly-leads; one with a 3.5mm stereo socket and the other with a 2.5mm stereo socket. The 2.5mm socket is used for programming the radio: tip is unused, ring is data and common is GND. 



Further information on plugs, adapters and programming cables including a DIY circuit can be found on the Links page of the author's website.

COM port

Selection of Com port number is done using the Settings menu. The program will remember the selection you make for the next time you run. 

There are two commands available - 'COM port Detector' and a pop-out called 'COM Port'. If you are certain about your COM port number then it is quickest to use the 'COM Port' pop-out. Otherwise use the 'COM port Detector' command. The following screen is shown:



Follow the on-screen instructions to detect and set the COM port for your programming cable. Be aware that each USB socket on your PC will be allocated a different COM port number, so you may need to use this screen again if you change your usual socket.