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 [email protected] <mailto:[email protected]> > On Feb 11, 2019, at 4:54 PM, Andy McMullin <[email protected]> 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 <[email protected] >> <mailto:[email protected]>> 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 >>> >>> >> >> ______________________________________________________________ >> 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] <mailto:[email protected]> > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > <http://mailman.qth.net/mailman/listinfo/elecraft> > Help: http://mailman.qth.net/mmfaq.htm <http://mailman.qth.net/mmfaq.htm> > Post: mailto:[email protected] <mailto:[email protected]> > > This list hosted by: http://www.qsl.net <http://www.qsl.net/> > Please help support this email list: http://www.qsl.net/donate.html > <http://www.qsl.net/donate.html> > Message delivered to [email protected] <mailto:[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]
