Linux designed for a TERMINAL exclusively???

ecsed · 07-05-2005, 03:41 AM

Hy Linux-friends,

is Linux exclusively designed for terminal-implementations?

Is an RTS-signal always a (terminal-) output and never a (modem-) input?

That can't be! Tell me another!

Best regards
Egon

jhumeston · 07-05-2005, 04:02 PM

A TTY can be either console or through any type of serial connection including ssh redirection.
Try hooking a serial connection to the linux machine and open a vt100 session to it. It should work just as you were at a console.

ecsed · 07-06-2005, 09:03 AM

Hy jhumeston,

thanks for your reply and your hint.

I'm not using a Linux-box, I'm programming hardware with Linux as OS.

My intension is to OUTPUT a DCD signal as a modem. But Linux only knows
the DCD signal as an INPUT signal. How can the direction be inverted without
miss-using other RS232 signals?

Best regards
Egon

Kdr Kane · 07-06-2005, 09:44 AM

Some serial interfaces may allow bi-directional signals on lines other than transmit, receive and ground.

However, you can should never rely on this being the situation. Serial ports are made to function according to the manufacturer and may only work in one direction. And this would fulfill the requirements of most serial devices. I've never seen any software that required DCD to be bi-directional.

Here are the standard signals. But, hopefully you have something like this already.

I don't see this as a problem with Linux at all. It sounds more like you're trying to do something you shouldn't.

ecsed · 07-06-2005, 09:58 AM

Hy Kdr Kane,

thanks for your info and your link.

The whole world outputs the DCD signal at the DCE modem device and inputs the DCD signal at the DTE terminal device as defined within the RS232 standard.

But I'v not to program a terminal, I've to program a MODEM!!! So I need an OUTPUT for the DCD´signal.

Has never been programmed a modem with Linux as OS???

Best regards
Egon

michaelk · 07-06-2005, 10:04 AM

AFAIK RS232 signals are not bidirectional. I would assume the serial code would be written as such. Does this hardware have a standard RS232 port?

ecsed · 07-06-2005, 10:15 AM

Hy michaelk,

yes, it will be a standardized serial interface.

According to the standard RS232 the DCD signal is an OUTPUT for the modem as the DCD signal is generated in the modem by receiving a data carrier via the communication path. This signal is handed over consecutively to the terminal (as an INPUT to the terminal).

Regards
Egon