This article describes how to make a USB programming cable for Yaesu FT-90R, which I did not find any information in Web.
It should work with other Yaesu handheld or mobile rig, which use similar protocol, such as FT-2600M, FT50, VX1R and VX5R .
The Yaesu FT-90R is compact but output max 50W, V/UHF mobile transceiver.
Yes, it is an old model, but it still available on eBay, as well as in Yahoo Japan bid market.
I bought a 2nd hand but in very good condition on 2 years before at eBay.
When got a new rig, the first thing faced is memory channel programming.
Manual input the channels is fine but not efficient. If it can be handled buy a computer program, it is better.
Almost all Yaesu series rig can be programmed the channels via computer.
However, the program is not included, it needs extra costs. The most popular 3rd party vender is RT systems, The software with programming cable costs US$ 49.
With help from the open source community, a free programming software CHIRP was developed. It is good, but it seldom to describe the programming cable schematic.
When searching programming information for the FT-90R, I just found an RS232 interface circuit for this purpose.
I tried make one and connect it to my notebook via an RS232 to USB adaptor, but it does not work.
As most of modern computer no longer provides RS232 serial port. A USB type is more suitable.
I study above circuit and the interface port (mic jack) of FT-90R, I found:
From the manual of FT-90R, Pin 2 is Data pin, Pin 4 is Gnd.
1/ the 9600 bps data pin should be a bi-directional pin for TX/RX data.
2/ the level seems is TTL (5V).
3/ pull high to the tx pin seems need.
Such requirement similar to ICOM IC-7000 programming / CAT remote control cable. Here is the circuit:
I modify a USB to TTL cord, to test it works for Yaesu FT-90. The chip of the cable is PL-2308HX , not the expensive FTDI one.
The pull high resistor is a SMD one
YouTube Demo
Tested it worked on both upload and download memory channel information.
Conclusion
CHIRP and a simple USB programming cable formed a free programming platform for my Yaesu FT-90. The circuit should work for others Yaesu rig use similar protocol, just replace the connector to an appropriate one.
If the rig supports remote control, the cable should work as well.
Have fun.
