Highfields Amateur Radio Club
Constructors Corner.
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Make a Yaesu CT-69 Microphone Adapter.
By Brian, MW0GKX.

This adapter allows the use of 8 Pin round Yaesu microphones on some Yaesu radios with the 6P6C modular socket. The images below show the view of the 6P6C plug with the locking tab underneath and wire connectors toward you. The 8 Pin round "socket" (actually the male, or plug but referred to as socket) is viewed looking into it as if you were about to put a plug in it.

I've labelled this project as moderate (orange) because it uses a modular plug, therefore requiring the use of specialised crimping pliers, otherwise it would have been easy (green). 8 pin Line plug


6P6C modular plug.
8 pin round line plug (locking ring type, see picture right)
3 core cable to suit.


1 Strip off a small amount of the outer sheath of the cable and, making a note of the order of the colours, crimp the modular plug onto the cable. NOTE: only pins 1, 2 and 3 are used. (You may find it easier to line up the wires if you carefully press pins 4 to 6 in with a screwdriver on the bench first).
2 Cut the cable to the required length (if not already).
3 Slide the line socket body onto the cable.
4 Strip some of the sheath from the free end of the cable and strip and tin the free ends of the wires ready to connect the socket.
5 Using the notes made in step 1 and referring to the table below, solder the wires to the correct pins on the line socket.
6 Assemble the line socket once connections have been checked and whiskers have been removed.

6 pin Modular PlugPinSignalPin8 pin Round Plug (socket)
modular plug1PTT6round socket
2Mic Audio8
3PTT / Function Ground7
4No Connection1
5No Connection2
6No Connection3
-No Connection4
-No Connection5

Compatible Radios

This adaptor will work with: FT-1500, FT-1802, FT-2800, FT-7800 (Dual Band with Modular Socket), FT-8800, FT-8900.

Other Yaesu 6 pin Modular Mic Socket Radios

For an adaptor to fit the FT-90, FT-100D, FT-2600, FT-3000, FT-7100, FT-8000 and FT-8100 see the Modified "CT-69" for other Yaesu Radios page.

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