phone line monitoring

[elsalamin]

I think someone is using my phone line because from time to time I get not tone at all.

I want to log the line voltage (one sample /minute is OK) with my computer and my sound card.

How do I do it?

 

[RF-OM]

Some multimeters have datalogging capabilities and serial port or other means to connect to computer. You may chose almost any time interval and thresholds. But if somebody use high impedance AC connection it is not easy to note. This method is not for sound card but will work.

Added after 2 minutes:

Beside this you may have bad connection in distribution box. In this case you need to call to service provider, they fix it for free, because they are responsible for this equipment.

 

[IanP]

Here is a simple line monitor circuit ..

**broken link removed**

Instead of red/green led you can use optocoupler(s) that will provide optical isolation between the phone line and your computer ..
The output of the optocoupler (4N25, HCPL2730 ..) is an O[pen] C[ollector] so you can use +5V from any USB port and, say, 10kΩ resistor as pull-up ..

Rgds,
IanP