There is a big problem with this, one that was unusual when Yaesu first created this setup, but very common now. The issue is that of false powering of receiving devices. In this day of low power micro controllers and other digital devices, the device can actually be powered through the I/O port when the device is supposed to be off. The I/O current flows into the input pin, through the protective diode and onto the Vcc rail, bypassing the main VCC pin. This means the device may be partially functional, and not under proper control. It can lead quickly to the destruction of the device.
This is the big reason for modern-day communications techniques between devices, and why protective measures must be taken to avoid false powering other devices. Yes, devices connected to BCD band data _can_ be false powered. We do see it. It makes me wonder if perhaps the old Yaesu method should be retired and no longer used. I certainly won’t be buying any of those devices. There is no reason that BCD data should not be carried at logic levels between devices if these measures have been taken. There appears to be two separate “standards” at this point, the Yaesu 12V system, and the 5 volt TTL logic level system. Devices that play in each should be clearly marked so the buyer can beware. Unfortunately many are not. This does provide an opportunity for the creation of interfaces which translate between the two methods, providing protection to both the transceiver and the device being driven. The problem comes from hams who don’t realize the issue and try to connect the two. Either they get frustrated because the connection doesn’t work and no harm is done otherwise, or they get really frustrated because the 12V driver blows up their device. Luckily we don’t see the latter happen that much. But arguing that the “old ways” are somehow better, when we know otherwise, doesn’t do very much good. In the Elecraft case, the drive and receivers are 5-volt TTL logic levels. As long as anything they attach do use those same levels everything works just fine. - Jack, W6FB > On Feb 28, 2018, at 11:33 AM, Joe Subich, W4TV <[email protected]> wrote: > > > On 2/28/2018 12:42 PM, Don Wilhelm wrote: >> So are you advocating that all manufacturers of ham gear should adopt the >> Yaesu implementation as a "standard"? Icom, Kenwood, Flex and Elecraft may >> have other thoughts. > > Yes, if another transceiver manufacturer chooses to emulate Yaesu's > protocol (BCD based "band data" with 160M = 1, 80M = 2, 40M = 3, > 30M = 4, 20M = 5, 17M = 6, 15M = 7, 12M = 8, 10M = 9 and 6M = 10), > they should also emulate the signal levels. > > Icom and Kenwood have spoken, Icom used its own proprietary "Stepped > Voltage" for the IC2KL/IC4KL and certain antenna tuners (which Elecraft > supports in the KPA500 and KPA1500), while Kenwood have never provided > any "band Data" outputs. > > I don't know/care what Flex are doing in their current "radios" - their > older products could be made to properly emulate the Yaesu Standard by > running a third party software application that drove an LPT port in > the computer that did the majority of the Flex's "work" - that LPT > sourced sufficient voltage/current (in "full power" ports) to be > compatible with the Yaesu implementation. > > 73, > > ... Joe, W4TV > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
