[asterisk-biz] T1 Y cable

[Andrew Kohlsmith]

On Monday 13 March 2006 18:47, Herman Webley wrote:
> I started looking at the physical layer specs on the T1 interface. One
> should be able to rig a (reliable) workable solution with a couple of
> cheap transistors. The trick would then be to signal the device which T1
> card it should signal the link to. This could be done via the serial,
> parallel or USB port.

I would far prefer to use something a little smarter: watch the actual 
datastream and switch over if either the transmit or receive stream is 
showing RAI or, depending on the level of smarts you want to build into it, 
any oddball condition.  This is how the professional failover systems work.  
Simply looking for the cable to be disconnected is a fool's errand since it's 
*very* rare that it is a physical line problem preventing connectivity.

-A.