Re: RS-232, No short No send?

From: Roger Hamlett (rogerspamignored_at_ttelmah.demon.co.uk)
Date: 10/06/04 

Date: Wed, 06 Oct 2004 16:42:49 GMT

"Boki" <bokiteam@ms21.hinet.net> wrote in message
news:ck14g8$bfl$1@netnews.hinet.net...
> Deaer Roger,
> Yes, I connected pin.3(TXD) to oscilloscope signal
and
> pin.1 connected to oscilloscope ground.(didn't swap lines)
> but there is no signal in oscilloscope. If I short pin.2 pin3, it works.
>
> I am confusing why it didn't send out signals when pin.2 pin.3 are not
> short. ( I floting all other pins.,.except signal and ground.)
>
> Best regards,
> Boki.
OK.
One thought, is that if the receive input is disconnected, the code will
be seing a continuous 'break'. It may be that this is disabling the
transmission. Try just pulling the RX line low, and then seeing if TX
starts. The handshake lines should have a suitable signal available (RTS
or CTS).

Best Wishes

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