How does linux detect hang-up? (DCD?)

How does linux detect hang-up? (DCD?)

Post by Steven G. Shree » Sat, 24 Feb 1996 04:00:00



To all, (please respond also by email)

I am connected directly to a terminal server (no modem).  I can use dip in the
interactive modem and talk directly to the terminal server without any
problems.  When I finally go to connect, it appears to do so; yet, within a
few seconds, Linux indicates that the connection has been lost or a hang-up
was detected or something like that.  My question is: How does Linux detect a
hang-up?  What can I do to make Linux think that there was no hang-up and to
carry on?  Is it the DCD or DTR or DSR or commands sent or timeout or what???

Puzzled,

Steve Shreeve

ps. - I am getting a similar response from Win95: it appears all cool and
      then it says, "Remote modem hung up"...  My serial connection has
      only 4 wires (RX,TX,GND,DTR)...  The RTS/CTS pins are jumpered.
      I tried jumping DTR to DCD, with no success (maybe DTR flashes?,
      or maybe this is just wrong)

 
 
 

1. How does linux detect hang-ups? (DCD?)

To all, (please respond via email)

I am connected directly to a terminal server (no modem).  I can use dip in the
interactive modem and talk directly to the terminal server without any
problems.  When I finally go to connect, it appears to do so; yet, within a
few seconds, Linux indicates that the connection has been lost or a hang-up
was detected or something like that.  My question is: How does Linux detect a
hang-up?  What can I do to make Linux think that there was no hang-up and to
carry on?  Is it the DCD or DTR or DSR or commands sent or timeout or what???

Puzzled,

Steve Shreeve

ps. - I am getting a similar response from Win95: it appears all cool and
      then it says, "Remote modem hung up"...  My serial connection has
      only 4 wires (RX,TX,GND,DTR)...  The RTS/CTS pins are jumpered.
      I tried jumping DTR to DCD, with no success (maybe DTR flashes?,
      or maybe this is just wrong)

2. Keyboard problem

3. Detecting carrier (DCD) loss?

4. Problems during installation using SLS

5. How to detect DCD on serial port

6. Looking for answer on ext2fs inode mode flag question.

7. DCD changed, how to detect?

8. Welcome to comp.unix.questions [Frequent posting]

9. allowing serial port logins when DCD (carrier detect) is not present

10. Detecting DCD

11. Using select to detect DCD changes

12. Serial I/O, detecting loss of DCD

13. mgetty /bin/login hangs, but DCD is up!