About the timing of the output data stream from PC terminals

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hi,

I just wondering if the data stream timing from serial terminal softwares are the same. Like if you send out a 100-byte stream, will the output be ideally the stream without any jetter or delay?

Coz I wanna check of timing of the output from these terminals so that I can distinguish the user typing input with the file transmission.

Cheng

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If you're asking 'will the bytes possibly be delayed by the windows system' the answer is yes.
Depending on the chipset, the transmit buffer will transmit as fast as it can, pending control signals - but the delay in the OS moving from its driver to the chipset is non-stochastic due to the multitasking nature of Windows.

That said, a file transmission will have many fewer delays than text entry - most people are incapable of more than five or six characters a second, so if your receive rate drops below that (equivalent would be something like 110 or 150 baud) then it's probably a person on the other end.

If you're trying to identify a user by the *way* they type - intercharacter intervals and rhythms, then you're probably out of luck.

Neil

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thanks, I'm trying to find the worst case in user text entry. It seems if you hold down one key and set the repeat rate to max, then it can output up to 45 chars per second. Of course this is just maximum, but it means the baud rate can gets to 600 (45 * 12). Maybe I should use 600 as the border between person text entry and file transmission.

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note that in some terminal modes it's done 'line wise' meaning that the terminal queues up the data for a line until enter is pressed, at which point it sends the entire line to the host in one burst.

Writing code is like having sex.... make one little mistake, and you're supporting it for life.

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OK, thanks for the notice