[Asterisk-Users] Asterisk testbed for teaching connecting to a PRI-ISDN

[Francesco Delfino]

Hi,
I would like to realize a voip testbed that should simulate the scenario
in which two companies have an asterisk PBX connected through a PRI-ISDN
to the Telco operator.
I have no experience of T1/E1 connection but I think that the above
could be relized with 3 asterisk boxes equipped with Digium TE405P cards.
One of the box will represent the Telco, the other two, the two
companies PBX.
I would like to know if it is needed something between the point-point
connections or it is possible to just cross-connect them.
I need the testbed to be representative of the real-world difficulties
in putting on an Asterisk BOX for connecting to a PRI-ISDN: is other
hardware needed (e.g. echo cancellers or failover switches)?

Asterisk BOX (Simulate the Telco)
with Digium TE405P
   |                   \
   | E1                 \  T1
   |                     \
[What to put here?]   [What to put here?]
   |                       \
   | E1                     \ T1
   |                         \
Asterisk BOX (Company)   Asterisk BOX (Company 2)
with Digium TE405P       with Digium TE405P


Regards,
    Francesco Delfino