> 
> >Every now and then I dial into my PPP account, I have the line go down and
> >I get a console message saying something about my serial line being looped
> >back.  What's it mean and what's causing it?  
> 
> I think I had the same problem. pppd tells you that the line is looped, if the
> modem is offline. I think it reads the CD line from the serial port. Try to 
> connect to your POP by using cu. Establich a connection and log off from cu. 
> Remember to setup the modem to stay online when DTR drops. If not it will drop
> the line while leaving cu.
> Then you should be able to start pppd without the error message and establish 
> an internet connection (if your ppp setup is correct ;-).
> After shutting down pppd, you have to restart cu and hangup the modem.
> That's the way I got it to work. I even tried to use the chat command as an 
> connect option to pppd, but it seems, that chat won't work.
> 
> Regards
>         Tobi
> 
> 
> 

One thing Macs don't do it carrier detect through the CD pin.  You can 
tinker around with your software and your serial cable to get it to work
that way.  I know that a Mac BBS called Hermes requires that you do this. 

If I'm correct, pppd never uses cu.  It talks directly to the serial port.
I've gotten chat to work with my pppd with help from Don Woodward (I hope
that's right; if not, please correct me Don)  :)  It's all in a single
script.  

-Jon