Using FTDI USB RS-232 cable for CAT control of a FTDX-1200?

Discussion in 'Computers, Hardware, and Operating Systems' started by KQ9I, Sep 4, 2020.

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  1. KQ9I

    KQ9I Premium Subscriber QRZ Page

    I have been using a Toughbook with a built-in old-school RS-232 port for Cat control of my FTDX-1200. I just connect a Rs-232 female/female cable between the radio and laptop and it instantly works with FLrig for CAT control for WSJT-X, and I can use HDSDR and Omnirig similarly.

    I got a new computer that is without the RS-232 port, so I purchased a RS-232 USB cable with an FTDI chipset. Doesn't work. The drivers are all installed, I made sure the baud rates match on the radio, in FLrig/Omnirig and also in Device manager for the Com Port itself. No joy.

    Anyone managed to get an FTDI USB RS-232 chipset to work with a FTDX rig for CAT control?

  2. NG1H

    NG1H XML Subscriber QRZ Page

    You can generally make a list by price and by how well they work and the ordering will be almost the same. In the dark past the Prolific chipset was the only one that really worked. (Edit: It looks like other people have problems with them with Win 10). I'm using a couple that 10+ years old and still working fine even with Win 10. Going by a brief sampling of public comments it looks like FTDI in general currently has a pretty good reputation. Problems seem to be the implementation of the chipset. The cheaper models in particular are prone to not working out of the box.

    Or it could the that the cheaper models are knock-offs and don't have the real chipsets.

    I would just get a good brand-name model and not bother with trying to get the old one to work.
    Last edited: Sep 4, 2020
  3. WR2E

    WR2E Ham Member QRZ Page

    Did you install the VCP drivers BEFORE connecting the USB-232 adapter?

    What about handshaking signals?

    Does the 1200 require them? Are they set correctly?
    A quick look at the 1200 CAT documentation seems to indicate that you need RTS and CTS

    Is your software looking for the correct COM port?
    Last edited: Sep 4, 2020
  4. WR2E

    WR2E Ham Member QRZ Page

    A way to test that the USB-232 adapter is working would be to download and install this simple little utility program called "Termite" onto your computer.

    Then use a clip lead to jumper pins 2 and 3 in the RS232 end of the cable together.

    What you type should be returned.

    This is called a 'loop back' test.
  5. KQ9I

    KQ9I Premium Subscriber QRZ Page


    Thanks for the input. I'm going to do the loopback test. As for the myriad of various settings (baud rates, stop bits, RTS, CTS, DTS etc etc) I've tried just about every combination I could think of. I've installed various commercial-trial VCP programs to tweak the VCPs. I've installed latest FTDI drivers. No luck. I've even tried setting up the Com Port for the FTDI USB cable as a VCP which serves the data via TCP to FLRig.

    Nothing works. When I set everything up on my old Toughbook with its built-in DB-9 serial port, THAT works perfectly. If I then plug the FTDI USB cable in and go that route instead, it doesn't. I've installed various drivers, and I believe the cable is a legit FTDI cable and not a Chinese knock off.

    Here's the thing I'm thinking may be the issue: from some cursory reading, the FTDI/Prolific chipsets that essentially emulate an old-school 16550 UART serial COM port via USB don't get it EXACTLY right. They are TTL, so the voltages are 0-5V. The radio and my Toughbook have "native" RS-232 and are expecting 12V. I believe there's also a polarity issue involved.

    There's a lot of discussion online about using a MAX232 chip to convert the levels from 5v to +/-12V necessary for "true" RS-232 serial communication. But what's blowing my mind is that there isn't already a commercial product out there that has a FTDI chip + MAX232 chip so that you get the exact same voltages and polarities with your USB RS-232 cable as you would get with the old type expansion card or built in serial ports.


    EDIT: Here's a discussion of what I'm talking about:
  6. KA9JLM

    KA9JLM Ham Member QRZ Page

    What You have should be made to work.

    Are you using Windows 10 by chance. If so you need the Windows Hoops Driver. :rolleyes:

    Maybe you need a Null Modem adapter.

    Good Luck.
  7. KQ9I

    KQ9I Premium Subscriber QRZ Page


    I installed a RS-232 Serial port in the PCie slot of my computer (I'm quite liking using this computer I got from my work just by asking for any old computers they weren't going to use- i5 core, small form factor, cool, quiet, sits behind the rig).

    Works flawlessly with a standard female-female RS-232 cable (note NOT a null-modem cable). There's even a jumper on the board so if you ever needed to you can supply either 5 or 12v via pin 9 to your device. 2 Port Low Profile Native RS232 PCI Express Serial Card with 16550 UART - PCIe RS232 - PCI-E Serial Card (PEX2S553LP)

    So, going back to my previous post I'm 99% sure that the issue with RS-232 CAT control of some Yaesu and other rigs lies almost entirely in the cables being sold as USB-RS232 cables. They are TTL RS-232 cables, not native/standard/legacy cables, they do not have the right voltage that your radio is expecting, and unless you get one of the rare ones that has a level/phase converter circuit built in, they will not work.

    "But my radio works with a cheap FTDI cable I got off Amazon!" Great. It's likely a newer radio with an RS-232 implementation designed specifically to work with TTL voltages/phases.

    Also, note that on the FTDX1200 forum, some people indicated that USB-RS232 cables from RT systems worked well. I suspect that those cables, and a few others that you can find with a bit of difficulty, have a simple circuit using a MAX232 level converter chip. As long as the radio "sees" 12V+/- and the phase is correct, it won't care what is going on in your computer, and conversely, if your computer is "seeing" the correct data after the FTDI chip and level converter do their thing, it's all good.

    Here is a cable that may work. I might get one just so I can see if I'm able to hook my FTDX1200 up to a tablet:
    Industrial Grade USB-RS485 USB-RS422 USB-RS232 FTDI Chip Isolated Conversion Module USB TO RS232/422/485 Magnetic Isolation (USB-RS232(FTDI Type), Signal converter)

    Hope this helps someone else. Incidentally, although I looked for it, I couldn't find info on the SCU-17, such as a schematic or datasheet, but I'll bet 5 bucks one of the things the SCU-17 does is handle the level conversion of the voltages and phase. Otherwise, you would be able to just plug in any RS-232->USB cable for CAT control...which we know doesn't work. Yaesu seems to like designing their radios so that you're almost forced to buy one of their overpriced accessories (like having an internal tuner that won't tune more than 3:1 SWR. My cheap Xiegu G90's tuner will tune a wet noodle). I use a $20 mini-din to audio cable for the sound card connection, and even after buying the PCIe card I've still save over $100. And being able to do everything with one USB cable is not worth ~$200 to me.

    KA9JLM likes this.
  8. W9GB

    W9GB Ham Member QRZ Page

    FTDI sells a wide-variety of USB bridge chips and cable.
    Based in the UK, they were the first hardware/software firm to work with Intel and Microsoft in developing their products lines.

    It is IMPORTANT to KNOW what you are BUYING, Especially Model Numbers.

    FTDI manufactures USB to UART/TTL serial cables (+5 or +3.3 Volt) for the thousands of RaspberryPi and Arduino hobbyists.
    These are sold at SparkFun as DEV-09718.
    have posted multiple times how those cables, using the FT232RQ chipset.
    A simple firmware configuration change, to invert the serial TxD and RxD lines, permits its easy usage for interfacing Kenwood Radio (6-pin ACC port, inverted serial, UART) to a personal computer’s USB port. DIY for $20.
    An excellent USB to RS-232 serial cable is the DS UT232R-200 by FTDI.
    It also uses the FT232R chipset and outputs RS-232C data and control lines.
    While this cable regularly sells for $30 from Mouser, Digi-Key and other outlets,
    I have purchased genuine versions for $10 on eBay, by government and commercial surplus outlets.

    In April 2018 I posted here on QRZ where the BARGAIN $10 was,
    after I tested the cables on my bench. Did the Amateur Radio community quickly buy? NO.
    That eBay reseller eventually sold hundreds of these cables.
    Where from? Cancelled government project.
  9. W9GB

    W9GB Ham Member QRZ Page

    Yaesu SCU-17 USB Interface Unit
    Instruction Manual , circa 2018 (Yaesu USA web site)
    AD10D513-D8C2-4FA5-A94A-F91398C81363.jpeg 15F1F9B9-633B-4797-9DB2-387A5E957FBC.jpeg
    In 2014, QRZ Tech Forum had over 10 pages, in the disassembly of the Yaesu SCU-17.
    The original poster of the question, after weeks of answers (17 pages), reported:
    “after quite a lot of puzzling, the nasty truth finally came out ... the frigging USB cable itself was BAD !!”

    I actually picked an SCU-17 up earlier this year ... for a few $$ ... from a frustrated radio amateur.
    It Worked Fine.

    The Yaesu SCU-17 contains these three (3) integrated circuits:
    • Dual Port USB 2.0 hub (Microchip USB2512B);
    • USB 1.1 Audio CODEC (Texas Instruments PCM2903B); and
    • USB/UART bridge (Silicon Labs CP2105).
    The Yaesu SCU-17 seems like a Japanese copy of USI / Timewave Navigator Sound Card Modem,
    which was Glenn's version (2006) of the earlier MixW RigExpert (2003).!topic/alt.ham-radio.rtty/zrMV7bj1XIw

    RigExpert / MixW (since 2003)
    The US Interface Navigator was designed by Glenn Wetherell, W3GWW (SK, April 2009) and
    supported by Clint Hurd, KK7UQ .

    Timewave purchased Navigator in November 2013.
    They now sell and support the Navigator product.

    Attached Files:

    Last edited: Sep 22, 2020

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