[Asterisk-Users] Power Failure, Line Switch, Relay device

[Steven Critchfield]

On Mon, 2005-01-10 at 14:48 -0600, Shawn L. Djernes wrote:
> Hello List,
> 
> Does anyone know of a device that works with the TDM400P FXO/FXS Modules to
> provide line backup for power failure?
> 
> I have an idea for such a device but do not have enough vision to do the
> soldering of the parts.
> 
> My ideal device would be able to sense when asterisk has brought the FXS
> port up and then switch a relay over so that the phone was connected to the
> FXS interface.  Then if the FXS or asterisk failed for any reason and the
> line was dead the relay would drop into default state connecting the phone
> to the external PSTN trunk.
> 
> Now for the reason I need such a device.
> 
> My Girlfriend has CP and cannot manually manipulate phone lines to switch a
> cable if the asterisk box were to go down. Also once she is in bed, she can
> not get up by herself to get to another phone.  I know there the Sipura 3000
> does auto line fail over but from discussions with a couple people who have
> them.  The sound quality is bad and the line fail over reverses the polarity
> and makes the Nortel phones unhappy.
> 
> If someone has a suggestion for a place to buy such a device or wants to
> build a prototype for me to test I would appreciate it.

Suggestion would be to get a 2 line phone. Line 2 could always be
plugged into the line. The reason I suggest this is that you have
another potential problem to be concerned about. Think power failure
just long enough to freak out the PC without tripping your device. Then
you are left with the line still seized by the PC but without service
either. 

Actually there could be any number of potential troubles you will run
into without tripping your device. IF you are really concerned you
should have a separate method of getting to the phone line than more
technology. 
-- 
Steven Critchfield <critch at basesys.com>