[asterisk-users] using asterisk on a shared line

[Trevor Hammonds]

Bill Lovett wrote:
>
>Can Asterisk be configured to hang up if another phone picks up?
>
>I'm a bit lost as far as terminology goes, but here's my setup. At  
>home, I have asterisk answering calls from the pstn and sending them  
>through to a sip extension or voicemail. All that is working fine.
>
>The box running Asterisk isn't on 24/7 so I have a secondary phone  
>connected to the line as well. If Asterisk is not running, I can  
>answer an incoming call from that phone. If asterisk is running, I can  
>answer the call from a sip extension.
>
>Can I have it both ways? Can Asterisk back off if the secondary phone  
>answers the call? Currently, if a call comes in and I answer it from  
>the secondary phone Asterisk will continue to ring the sip extension  
>and eventually drop into voicemail. 

Asterisk is a PBX, not an answering machine, so I would advise against this.
It would be best to have Asterisk handle the phone line exclusively, 24/7.
However, with that said, it is possible to accomplish what you are asking.  

Placing a telephone privacy/exclusion adapter on the line cord into Asterisk
will cut off the phone line whenever a parallel telephone on the same line
is picked up.  This means that the instant you pick up any other phone on
the line, it would cut off the line to Asterisk.  

Radio Shack used to sell a couple varieties of these.  One was a two-way
adapter with one side for "phone" and the other "answering machine".  You do
not need to plug anything into the "phone" side for the device to work.  The
second device was just an inline exclusion device.  I was unable to find
these at Radio Shack's website.  However, I found something similar at the
following URLs:

(See SER2A, SER2D, and SER3P at Sandman.com)
http://www.sandman.com/lineshar.html

http://www.trianglecables.com/telanmacorph.html

http://www.iec-usa.com/cgi-bin/iec/COM9928

http://www.iec-usa.com/cgi-bin/iec/COM0006

Good luck!

Sincerely,
Trevor Hammonds