On 31 Jul 1999, Michael Kummeth wrote:

> Jul 30 12:04:57 zette pppd[220]: Connect: ppp0 <--> /dev/tty01
> Jul 30 12:04:57 zette pppd[220]: Serial line is looped back.
> Jul 30 12:04:57 zette pppd[220]: Connection terminated.
> Jul 30 12:04:57 zette pppd[220]: Serial link disconnected.
> Jul 30 12:04:59 zette pppd[220]: Exit.
> 
> the script used is from: "http://www2.giganet.net/~mark/NetBSD/ppp.html"
> with option for pap. 
> 
> ppp-up:
> #!/bin/sh
> 
> /usr/sbin/pppd /dev/tty01 57600 connect '/usr/sbin/chat -v "" ATZ OK ATF0
> OK ATDT0191011 CONNECT' \
> crtscts defaultroute noipdefault modem remotename * user
> 0002119694863200685494000001

Instead of ATF0, try AT&FE0&C1&D0 or AT&F1E0&C1&D0, and also change
'crtscts' to 'cdtrcts'. (The command line overrides the options file.)
With a typical mac hardware handshaking cable, the signals are tied in
such a way that asserting rts will cause the modem to hang up! &D0
prevents this.

Another interesting possibility is that your username is so long, that
pppd decides you must have left the port in 7-bit mode by mistake.  
To see more precisely what's happening, throw a "debug" into the
options, and then add a line to /etc/syslog.conf:

  "daemon.debug /var/log/messages"

or choose some other file to save the debug messages to.
 
> pap-secrets:
> 0002119694863200685494000001 * passwd
> 
> the ISP says, PAP is necessary.
> bad networking conf?

"debug" will show you the LCP negotations, including the pap stuff,
and so might provide a clue.