Dialup drops connection when AC adapter used

[techster]

I have a Toshiba Satellite 1415 S105 with XP Pro. My dialup modem drops the connection and sometimes won't connect at all when I use the AC adapter. All other laptop functions are fine. Any ideas?

 

[CCT]

Run Everest with just the battery connected - call up Computer, Sensor and watch the voltages - while watching, plug in the adapter.

If there is no drastic change, then in all liklihood the modem got a small zap that is letting it fail. An external USB modem would work I think.