Re^2: Assist human unobtrusively in a 3rd party Windows GUI

The protocols run at 38400 baud which is as fast as RS-232 serial can go.
There is no idea of a "connection" or a "packet of information".
A multi-byte command is sent and then a multi-byte response is expected.
There are many ways for this to go wrong!
When the response is "nonsense" (including some time out values), a RESET is required.

The typical serial device does not implement any kind of idea a "connection".

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Re^3: Assist human unobtrusively in a 3rd party Windows GUI by GrandFather (Saint) on Dec 13, 2020 at 02:28 UTC
Actually the RS-232 standard doesn't specify bit rates at all, although it does suggest bit rates above 20,000 aren't supported. I routinely use a baud rate just below 1e6 Baud for a debug port on embedded systems I'm working on. That connects using a FTDI serial to USB cable. It would commonly be called RS-232, even though no part of the system bears any relationship to the RS-232 standard which is all about plugs and signalling levels. To my way of thinking a serial cable between two devices is essentially the definition of a "connection", although that has become a much abused word in this context, rather like RS-232 actually. Optimising for fewest key strokes only makes sense transmitting to Pluto or beyond	[reply]
Re^3: Assist human unobtrusively in a 3rd party Windows GUI by jmlynesjr (Deacon) on Dec 14, 2020 at 00:29 UTC
Are you receiving a checksum or CRC-16? If not, how do you know that any message is received correctly? Are you connecting via modems? At higher bit rates cable lengths become a problem. It's very difficult to make these open-ended systems operate reliably. Do you have any capability to run any loop-back tests on your circuits? James There's never enough time to do it right, but always enough time to do it over...	[reply]


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