[Elecraft] KPA500 serial interfaces

[Don Wilhelm]

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
>
>