I'm currently using a Mac IIcx running 1.4 as a NAT box to share a PPP
dialup connection on my home network.  I've been using the setup with a
Practical Peripherals 28.8 modem with excellent results over the last 6
months.  For Christmas, I got a 56k Viking modem and decided to try it
out on my NAT box.  It worked great the first day I tried it, but the
second day all I got was static for a dial-tone.  Must be a faulty modem
- so I returned it and exchanged it for a USRobotics 56k modem.

Now after 4 days of successful NAT use, the USR modem is doing the same
thing.  Nothing but static once the modem initializes and the speaker
comes on.  I know its coming from the serial cable, because if I
disconnect it from the modem, the static goes disappears.  I leave my
NAT box running 24/7, but I do turn off the modem.  Could powering on of
the modem cause such a problem?  Could rebooting NetBSD with the modem
attached and powered on cause a problem?  Could static charge building
up while the NAT box runs cause the problem?  I've never had any such
problem with the 28.8 modem, even doing the above.  Any insite is much
appreciated.

Erik