[Asterisk-Users] Identify call router? How?

[Stephen Varga]

On Sat, 2003-09-20 at 11:48, Steve Totaro wrote:
> routers or a  t1 cards can do that without a csu/dsu.  a csu/dsu is really
> just something that the telco can use for trouble shooting and loopback
> testing.  i think the fcc also requires it by law.

First off CSU/DSU is not required by FCC law (we'll ignore the fact that
the FCC can't make law only the legislature can)...it is required for
operation.

You need a CSU to terminate the T1 line from the telco and the DSU to
turn the T1 data into something you can use. The routers an T1 cards you
mentioned have the CSU/DSU built in and thus don't require an external
CSU/DSU to operate.

The telco can send inband signals to tell the CSU to loop the signal
back to telco for testing/troubleshooting issues on the circuit. Usually
the CSU can be configured to ignore the loop codes if the so desired.
But most telco only test to their smart jack anyway (this is usually
where the telco's circuit responsibility ends, anything beyond is the
customer's responsibility).