[Elecraft] KPA500 serial interfaces

[Michael Blake]

Andy, in support of your comments I was an active Bell System DATEC representative back in the 70s and 80s and multipoint polled RS-232 was very common here in the colonies :)

Michael Blake
k9jri at mac.com <mailto:k9jri at icloud.com>






> On Feb 11, 2019, at 4:54 PM, Andy McMullin <Andy at rickham.net> wrote:
> 
> Not wishing to get into an argument but consider Binary-Synch, Uniscope or UTS400 protocols. They are poll and response, RS232c communications systems. Used from mainframe to (dumb) terminal. They are synchronous RS232 of course rather than asynch and so use the clock and other signals ignored by the [IBM PC] cut down implementation of the RS232 connector. RS232 of course only defining the names and voltages on the connector.
> 
> From memory a Uniscope (U100) “poll” from the mainframe would be the characters: sync, sync, sync, sync, SOH, RID, SID, DID, STX, text, ETX, BCC. 
> 
> Now that was dug out of the 1970’s if nothing was!
> 
> Andy, G8TQH
> 
>> On 11 Feb 2019, at 21:35, Don Wilhelm <donwilh at embarqmail.com <mailto:donwilh at embarqmail.com>> wrote:
>> 
>> Andy,
>> 
>> "Polling" normally refers to a situation like Ethernet and others where a response from a particular *addressed* device is requested.
>> For RS-232, it is "handshaking" (if implemented) telling the DTE when it is OK to send data - since there is only one transmitter on an RS-232 signalling line, there is no need for addressing. The transmitting device expects to communicate to only one receiving device on the other end (although other receivers can 'listen in'.
>> 
>> I have worked with RS-232 for over 35 years both professionally (both modems and DCEs for 20 years) and with ham radio gear and PCs after retirement from that life.
>> 
>> If we wish for clear communication, the terms used are important. Ham Radio "speak" often confuses the proper engineering terms. You hear of ham radio software that "polls" the radio - in reality, it is simply issuing a command to the radio and expects a response to that command.  That is a command/response scenerio, and is not really polling.
>> 
>> Don W3FPR
>> 
>> On 2/11/2019 3:55 PM, Andy Durbin wrote:
>>> "I have no idea how your "polling" device works, but with RS-232, thereis no polling, "
>>> 
>>> Point 1 is true. Point 2 is, in my opinion, not true.
>>> 
>>> A poll is a request for information. The device issuing the poll/request is the polling device.   For example, sending IF; to a TS-590 is a data request, or poll, for the current IF status.  The TS-590 responds with the full IF word.
>>> 
>>> Andy, k3wyc
>>> 
>>> 
>> 
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