No Carrier - PPP

This is a discussion on No Carrier - PPP ; Alright, No Carrier. This is the reason one box doesn't connect. When I manually call using the modem it works. The negotiation takes place and I get my login. Clearly I don't get ppp because I am not test ppp ...

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Thread: No Carrier

  1. No Carrier

    Alright, No Carrier. This is the reason one box doesn't connect.
    When I manually call using the modem it works. The negotiation takes
    place and I get my login. Clearly I don't get ppp because I am not
    test ppp but the modem. Then I try using pppd, chat, and mgetty to
    perform dial in and out services. Everytime the connection starts
    when it should. The demand dial works, but I get a No Carrier error.
    Now this only happens when I try and use the modem for ppp, not when I
    use a terminal emulator. I have looked through the init string for
    the modem, and it is ok. I have actually tried to put that in
    manually and then call out manually and it works. Just when chat is
    used to connect do I get the No Carrier error. That is all that chat
    gives with the -v enabled.

    06/22 16:16:32 yS0 checking lockfiles, locking the line
    06/22 16:16:32 yS0 makelock(ttyS0) called
    06/22 16:16:32 yS0 do_makelock: lock='/var/lock/LCK..ttyS0'
    06/22 16:16:32 yS0 lock made
    06/22 16:16:32 yS0 waiting for ``RING''
    06/22 16:16:32 yS0 got: [0d]
    06/22 16:16:32 yS0 CND: OK[0a]RING ** found **
    06/22 16:16:32 yS0 cannot set controlling tty (ioctl): Operation not
    permitted
    06/22 16:16:32 yS0 send: ATA[0d]
    06/22 16:16:32 yS0 waiting for ``CONNECT''
    06/22 16:16:32 yS0 got: [0d]
    06/22 16:16:32 yS0 CND: RING[0a][0d][0a]NO CARRIER
    06/22 16:16:57 yS0 found action string: ``NO CARRIER''
    06/22 16:16:57 ##### failed A_FAIL dev=ttyS0, pid=269, caller=none,
    conn='', name=''

  2. Re: No Carrier

    dirtytoyota@hotmail.com (PullnOutHair) writes:
    >Alright, No Carrier. This is the reason one box doesn't connect.
    >When I manually call using the modem it works. The negotiation takes
    >place and I get my login. Clearly I don't get ppp because I am not
    >test ppp but the modem. Then I try using pppd, chat, and mgetty to
    >perform dial in and out services. Everytime the connection starts
    >when it should. The demand dial works, but I get a No Carrier error.
    >Now this only happens when I try and use the modem for ppp, not when I
    >use a terminal emulator.
    >


    Time it. I'll bet that when ppp/chat dials, it takes only
    30 seconds before the connection is dropped, and it takes
    longer when you use the terminal emulator.

    If that's true, then you need to make chat wait longer
    for the connect message from the modem.

    -Greg
    --
    Do NOT reply via e-mail.
    Reply in the newsgroup.

  3. Re: No Carrier

    >
    > If that's true, then you need to make chat wait longer
    > for the connect message from the modem.
    >



    Can you make chat wait longer? I thought that the No Carrier was a
    modem issue not a chat or pppd issue. The modem actually reports the
    status of the connection. I have tried to extend the length of time
    my modem waits from .2 seconds to 1.5 seconds and that seemed to help,
    but I still have a no carrier problem. I also extended the time for
    the modem to establish the end to end communications to 120 seconds.
    I know these are long values, but the modems are having to figure out
    communications over a cellular network instead of land lines, so I
    figure the signal is just worse and slower. These settings helped but
    didn't solve the problem 100%. But better is better.

    Thanks

  4. Re: No Carrier

    dirtytoyota@hotmail.com (PullnOutHair) writes:
    >>
    >> If that's true, then you need to make chat wait longer
    >> for the connect message from the modem.
    >>

    >
    >
    >Can you make chat wait longer?
    >


    The man page for chat mentions a TIMEOUT command, and
    gives examples of its use. I believe that can make
    chat wait longer than the default.

    >
    >I thought that the No Carrier was a modem issue not a chat
    >or pppd issue.
    >


    The modem can report NO CARRIER when chat makes it abort
    the dialing attempt. Or even if the chat script sends
    a character like a Carriage Return before the modem has
    finished completing a connection with the other modem.

    >
    >I also extended the time for
    >the modem to establish the end to end communications to 120 seconds.
    >


    That's excellent. Now the only difference is how long you are
    willing to wait for the modem to complete the connection, versus
    how long chat is willing to wait.

    Making the modem wait longer is good, but you must also make chat
    wait longer, or chat will end the dial attempt too soon.

    -Greg
    --
    Do NOT reply via e-mail.
    Reply in the newsgroup.

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