[asterisk-users] Using a Loopback Plug for an RJ-45 EthernetInterface for testing a Digium Card

[Michael Collins]

> I can't speak to exactly what the alarm status stuff does if the port
> you're looping expects to have a PRI plugged into it: I would expect
> "Green, but no actual traffic", but I could be wrong, I'm a bit new on
> that front.

Just for the record, this is generally a correct statement.  I can't
speak for every T1 interface out there, but every T1 interface I've
personally used does respond to the so-called "hard loopback" that is
described elsewhere in this thread.  The hard loopback really is just a
layer one test.  On Zaptel you should definitely see a green light when
you plug in a loopback test plug.  This is kind of a sanity test - not
necessarily for the equipment but rather for the guy trying to make it
run! :)  It is a very basic test, and it fits in with "is the computer
plugged in and turned" and "did the zaptel driver(s) get loaded" and
such.  A green light simply means that the layer one connection is
working - the physical connection, the framing and coding, timing, etc.
Obviously this needs to be working before you can get meaningful traffic
moving over the interface...

Happy T1/E1-ing.

-MC