I am helping a friend who is having horrible dialup problems. He is lucky to stay connected for 10-15 minutes at a time. This problem has continued through several modems & at least 2 computers. He is ...

I need a little help. I am looking for a tool\utility that will allow me to test for busy signal on phone line and then email/txt me that the line is busy. I would like for it to run on a schedule say ...

The circuit was designed to provide a monitoring scheme for a telephone line where several phones are installed, to indicate when one is being used. 4N25 – a general purpose optocoupler that consists ...

It seems that everyone is testing IEC61000-4-11 in order to obtain CB certification and international certification (CE marking etc.). The IEC61000-4-11 standard specifies voltage dip, short ...