[Elecraft] Advice needed: Remote Station Enhancement

Wed Feb 28 12:42:38 EST 2018

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.

73,
Don W3FPR

On 2/28/2018 11:15 AM, Joe Subich, W4TV wrote:
>
> > THe point is that the two do not work together.
>
> The point is that the devices don't work together because the third
> party manufacturers did not bother to understand the Yaesu design
> and take the necessary steps to be compatible.  Yaesu's only purpose
> was to provide band switching data from the transceiver to a Yaesu
> amplifier.  Their was no reason to design their system according to
> some inapplicable "standard" from the data processing world.
>
> Third party manufacturers need only provide a low impedance source
> of +12V for a logic high and open circuit for a logic low on the
> "transmit" side to emulate the Yaesu transceiver.
>
> On the receive side, any device that would connect to a Yaesu 
> compatible transceiver needs to tolerate +12V on the input and have a 
> moderately
> high (1 - 2K) pull down on any logic inputs (if it uses logic inputs);
> opto-isolator inputs simply need the appropriate current limiting
> resistors for 12V inputs (or +5V inputs given that many transceivers
> have failed to provide +12V logic high outputs).
>
> The bottom line is that this is not a "standards based" application.
> If one is going to provide (or use) BCD "band data" the device must
> closely emulate the Yaesu transceiver or clearly state that its
> signaling levels are not [guaranteed] compatible with Yaesu.
>
> 73,
>
>    ... Joe, W4TV
>
>
> On 2/27/2018 10:53 PM, Don Wilhelm wrote:
>> Joe,
>>
>> You do admit that many amateur products do not conform to typical 
>> communications standards in the digital world. My experience does go 
>> back to my design and evaluation of IBM terminal communication 
>> between a DCE and a DTE device.  Although this was not necessarily 
>> RS-232 levels, the same thing is true. The drivers provide the low 
>> and high levels to the line (an open circuit or a ground) while the 
>> receiver at the far end of the line provides the logic high level.  
>> All other receivers will not provide voltage, but can listen in on 
>> the communication. This is not consistent with amateur products with 
>> one providing pullup resistors ath the driver location and some 
>> receive locations requiring the opposite I.E, those providing pullup 
>> resistors to +12 volts.
>> THe point is that the two do not work together.  It is not a systems 
>> approach.
>>
>> 73,
>> Don W3FPR.
>>
>>
>> On 2/27/2018 10:09 PM, Joe Subich, W4TV wrote:
>>>
>>> You're dealing with a "standard" that was originally developed for use
>>> only within one company's products - much like Elecraft's Aux Bus.
>>>
>>> As such, any "industry standard" is moot.  The design is for active
>>> high/voltage source (to +12V originally) and was not intended for any
>>> purpose than providing band switching for the FL-700 then the Quadra.
>>> It would seem to me that any product that claims to inter-operate with
>>> the Yaesu "Band Data" would emulate or at least be compatible with
>>> that behavior - including the ability to *source* sufficient current
>>> at +12V.
>>>
>>> These devices are not operating in the "communications (non-ham) 
>>> world",
>>> they are strictly amateur products.
>>>
>>> 73,
>>>
>>>    ... Joe, W4TV
>>>
>>>
>>> On 2/27/2018 9:28 PM, Don Wilhelm wrote:
>>>> The problem is that most devices (in the ham world) expect the 
>>>> driver device to provide voltage.
>>>> In the communications (non-ham) world, the expectation is that the 
>>>> driver device produces either a logic low (short to common) or a 
>>>> logic high ( open circuit).
>>>>
>>>> Look at the data sheets for "line drivers" and "line receivers" to 
>>>> check out what I am saying.
>>>>
>>>> Open collector or open emitter does not make a difference in 
>>>> function, it is only a circuit design decision.  Yes, open 
>>>> Collector (or open drain) is commonly use in logic where the active 
>>>> state is zero volts (transistor or FET conducting to ground).
>>>> The open emitter design is the opposite.  A conducting device will 
>>>> provide a voltage on the line (or signal) being driven.
>>>>
>>>> The point is that in a properly designed communications system, the 
>>>> drivers provide either conduction to ground or an essentially open 
>>>> circuit to the communications line (think of a relay being either 
>>>> open or closed).  The receiver provides the voltage to detect 
>>>> whether the driver is in an open circuit or closed circuit state.
>>>> If there are multiple receivers in the system, only one can be 
>>>> "boss", and that one determines the open circuit voltage and 
>>>> contains the pullup resistors for the system.  Other receivers work 
>>>> in listen mode and will contain no pullup resistors or active drivers.
>>>>
>>>> This whole situation goes back to the "one driver, one receiver" 
>>>> condition.
>>>> Only one driver can exist on a communications system without conflict.
>>>> Multiple receivers are possible, but only one (at the far end of 
>>>> the line) should provide the pullup resistors.  All other receivers 
>>>> must be only in the listen mode.
>>>>
>>>> 73,
>>>> Don W3FPR
>>>>
>>>> On 2/27/2018 8:06 PM, Joe Subich, W4TV wrote:
>>>>>
>>>>>  > But many (most) ham devices do not do it that way, they expect the
>>>>>  > pullup resistors will be provided by the driver gear.
>>>>>
>>>>> Actually, most devices that use BCD "band data" expect an open
>>>>> emitter driver not an open collector driver.  Open emitter will
>>>>> *source* voltage for logic high and be open circuit for logic
>>>>> low.  This is the convention from the early Yaesu rigs which
>>>>> were the first devices to support "band data" (it is the way
>>>>> the FL-7000 and Quadra amplifiers operate).
>>>>>
>>>>> You will find the W9XT BCD10/BCD14 decoders with their opto-isolator
>>>>> inputs work just fine with the "open emitter" drivers. Other devices
>>>>> designed with Yaesu transceivers in mind have appropriate current
>>>>> limiting (series) on the input lines and "pull down" (parallel)
>>>>> resistors on the logic gates.  Some "standard" devices (Top Ten
>>>>> BD-Y and the original microHAM Band Decoder) will provide both
>>>>> current limiting resistors and internal pull-ups but I have not
>>>>> seen any amateur product with series diodes in the band data lines.
>>>>>
>>>>> 73,
>>>>>
>>>>>     ... Joe, W4TV
>>>>>
>>>>>
>>>>> On 2/27/2018 4:17 PM, Don Wilhelm wrote:
>>>>>> Knut,
>>>>>>
>>>>>> That is the way it *should* be, and was that way in the K3 
>>>>>> originally.
>>>>>> But many (most) ham devices do not do it that way, they expect 
>>>>>> the pullup resistors will be provided by the driver gear.
>>>>>> So, because of that, Elecraft added pullup resistors to the band 
>>>>>> data outputs of the K3 long ago.
>>>>>> So yes, we are left with a situation that often requires steering 
>>>>>> diodes.
>>>>>>
>>>>>>
>>>>>> 73,
>>>>>> Don W3FPR
>>>>>>
>>>>>> On 2/27/2018 3:48 PM, ab2tc wrote:
>>>>>>> Hi Don and all,
>>>>>>>
>>>>>>> Hear,hear, Don. The receivers should have the pullup resistor to 
>>>>>>> whatever
>>>>>>> the appropriate voltage needed (within reason) *and* a steering 
>>>>>>> diode in
>>>>>>> series with the input. This will prevent another device with a 
>>>>>>> higher
>>>>>>> voltage from feeding current back into the device which could 
>>>>>>> damage
>>>>>>> semiconductors. Without the steering diode all receivers must 
>>>>>>> use the same
>>>>>>> pullup voltage. Of course a single receiver is not a problem 
>>>>>>> either.
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>>>>
>>>
>>
>>
>