Matching getty speed to dial-in speed

Matching getty speed to dial-in speed

Post by Gaylord Hold » Thu, 01 Aug 1991 04:07:06



I have a US Robotics modem attached to an RS/6000.  People dialing in
do so at 9600, 2400, and 1200 baud.  How do I tell getty to do the right
thing?

If there isn't a way to get getty to cycle line speeds, I was thinking of
writing a program which would read the connection codes from the modem and
then execing getty with the proper args.  The problem is I can't figure how
to open the port since it seems to be modem controlled.  I know it can
be done since cu does it.

Any clues?  Thanks.
Gaylord

 
 
 

Matching getty speed to dial-in speed

Post by Mats Bengtss » Fri, 02 Aug 1991 00:10:42



>I have a US Robotics modem attached to an RS/6000.  People dialing in
>do so at 9600, 2400, and 1200 baud.  How do I tell getty to do the right
>thing?

We have the same setup. We simply tell the modems to always connect in the very
same speed, 19200 baud, to the computer. Then we tell getty (well smit chtty)
to use the port at one speed only. In this way, the modem, not the getty,
handles everything that has to do with speed changes. For security, we tell the
modem to always reboot after carrier loss, and every reboot is done from nvram
(dip switch 10).

Quote:>If there isn't a way to get getty to cycle line speeds, I was thinking of
>writing a program which would read the connection codes from the modem and
>then execing getty with the proper args.  The problem is I can't figure how
>to open the port since it seems to be modem controlled.  I know it can
>be done since cu does it.

Well, if you want, you can tell getty to cycle speeds, simply by defining all
those speeds at the same time for the port, and then set the time out time in
smit chtty to something you like. But, you are likely to get some problems,
using the modem itself for this part is a lot easier.

When it comes to opening the port, look at the line independent drivers. You
normally have dtropen on a getty port (stty get) I guess it means open when dtr
goes on, no documentation found. When you use cu, it exchanges this, and the
code lion, to instead use "rs", which I guess stands for remote system, and
allows you to open at any times. Another interesting mode is "dtr", which is
likely to set dtr high, not only when opened. All the last is guessing, the
rest is actually tried.

By the way, figure out how to add rts as mode, it is a lot bettern than
xon/xoff. But even if you do use it, never remove the "xon" driver, things will
get very shaky then.



 
 
 

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