[geeks] Suggestions for USB to serial adapter?

der Mouse mouse at Rodents-Montreal.ORG
Thu Aug 20 00:43:53 CDT 2009


> Make sure it can send a break signal!  A lot of the cheaper ones
> can't.  I bought a belkin one and it works great except it can't send
> a break so it's pretty much useless as a console adapter.

Check out how low a baud rate it can handle.  If you want, say, a 250ms
break, then you can get it by sending a 0x00 octet at 36 baud (assuming
8 data bits, no parity); for a 1s break, use 9 baud - the formula is
that your baud rate should be such that nine bit times is the desired
break duration.

This does demand a little help from software on the host, to recognize
that a break condition is desired and convert it into two baud rate
changes bracketing a 0x00 data octet....

Of course, you may find that it won't go below (say) 300 baud, or some
such, but you also might instead get a pleasant surprise.

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