Question : Problem: Controlling a modem

I want to be able to control my PC's 56k standard modem's line so that I can connect/disconnect the line input. Let me try and explain that better. Normally, standard PC modems have two telephone line connectors - one for LINE and one for PHONE. The LINE connector plugs into the telephone line and then your telephone plugs into the PHONE connector. I want to be able to disconnect the phone (attached to the PHONE connector on the modem) from software. So I was wondering if there is an AT command or maybe some other way (I'm a Visual Basic programmer so maybe I can write something) that will connect or disconnect the phone, or the modem alltogether, from the telephone line. In other words, so that if you life the phone's handset, there is no dial tone. But at the simply click of a button on the PC where the modem is, it can reconnect the modem or phone to the telephone line and the phone will have a dial tone again.

Also, is it possible to record an audio conversation as a WAVE file or something similar if someone is talking on a phone connected to the PHONE connector of a modem?

And lastly, does anyone know where I can get the circuit diagram to any 56K modem?

Thanks

Answer : Problem: Controlling a modem

Disable the handset port on a modem
This is 100% dependent on your modem chipset (which defines which AT command set is available).  What you are looking for is the AT command string to disable dialtone pass-through.

See http://www.sipura.com/Documents/rnote/rn3k-3.1.3a.htm as a starting point

"....Also, is it possible to record an audio conversation as a WAVE file or something similar if someone is talking on a phone connected to the PHONE connector of a modem..."

I recently began testing this type of software.  ModemSpy is one option, under certain conditions, SoundSnopper.  Both available at the same site.
Also, see http://www.snapfiles.com/shareware/comm/swphonetools.html
I found VentaFax to be the most useful and recorded calls on the first try BUT it is configuration intense and NOT intuitive.  VentaFax also does a lot of things I do not need, but it does the ONE thing I do need - record calls on demand.
At the same site, I also tried TRx Personal Phone Call Recorder.  I am still digging it out of the registry and system disk - the installation behaved exactly like malware.  No known problems, did not test functionality.  Again, looks like malware, in my opinion.

"...And lastly, does anyone know where I can get the circuit diagram to any 56K modem?..."
See http://www.wa4dsy.net/rfmodem.html
See http://www.commlinx.com.au/schematics.htm