ALL TECHNICAL INFORMATION AND SOFTWARE ON THIS PAGE IS USED ON YOUR OWN RISK!!!
YOU HAVE BEEN WARNED. LIVE WITH IT…
Development of the software on this page has been discontinued.
Source code now available further down.
About the Yaesu FT-757GXII Cat interface
The cat interface on the FT-757 is a standard Mini-DIN 6 pin (PS2-style) connector with TTL levels.
An RS232 converter like the MAX232 or similar (I use MAX233) can be used to interface a computer.
Adding a simple opto coupler to this to control the PTT also found in this jack and a 78L05 to supply the power from the 8V or 13.5V RCA jacks makes this a complete cat interface.
People often use darlington opto-couplers but the 4n35 will probably work just fine.
ONE IMPORTANT THING: If you have problems getting data through from the tranciever to the computer you might have to add a pull-down resistor to the TTL serial output of the cat connector. About 2K will do. Apparently the 757 does not have any external or internal pull-down resistors on this output.
The problem can apparently be found on other older Yaesu rigs as well.
Yaesu FT-757GXII Control Software for Windows
I have bodged together a simple control software for the FT-757GXII. It is freeware and source code is available
on request. It was made using Visual Basic 2005 Express and requires .NET 2.0.
Mode and frequency setting
Split mode toggle
Clarifier mode toggle
Gen/ham step toggle
Dial lock toggle
VFO A/B selection
Band Up/Down buttons
Memory Up/Down when in Memory Mode
Status polling of all these values and TX status
Switching between VFO and memory mode – Thanks to Robert, N2JTX.
Bugs are included at no extra cost.
Download Source Code: ft757gxiicontroller-src