Verilink APS 2000 T1 Line Protection (880-502411-001) Product Manual - Manual (Page 74)

Diagnostics
5-10 Verilink APS 2000 User Manual
Remote
Loopbacks
Remote loopbacks include the T1 inband loop up and loop down, as
well as the V.54 loopbacks.
T1 Inband Loop Up This command, when asserted at the near end, causes the industry
standard T1 inband loop up code to be sent, inband, to the far end.
The far end responds by looping its entire T1 aggregate signal back
toward the near end. The APS functionality also recognizes the
looped condition and forces both ends to switch to the protection
line.
T1 Inband Loop
Down
This command, asserted at the near end, causes standard T1 loop
down code to be sent, inband, to the far end. The far end responds
by dropping its loopback state (if present) and returning to normal
signal transmission. The APS control mode will determine if the
circuit automatically resets from the protection line or must be
reset manually.
V.54 Inband Loop
Up
This command, asserted at the near end, causes the Industry
Standard V.54 FT1 DS0 loopback code to be sent to the far end, in
only the DSO channel(s) selected. The remainder of the outgoing T1
signal is unaffected. Note that the far end APS equipment ignores
this V.54 loopback command, but passes it through the circuit
toward any V.54 compatible terminating DSU/CSU located further
down the circuit. The terminating DSU/CSU will respond by looping
back the selected DSO channel or FT1 bundle toward the near end.
The DSO loopback condition does not cause the APS system to
switch.
V.54 Inband Loop
Down
This command is identical to the V.54 inband loop up command
except that the V.54 code is for loop down and causes an active
DSO loopback condition to be dropped at the terminating DSU/CSU.
Again, this function does not effect APS.
Configuration of
V.54 Loopback
Testing
DSO loopbacks and test functions are configurable and controllable
both locally via the Craft interface, or remotely via SNMP (see the
Verilink Enterprise MIB) or a Telnet session.
The Craft interface provides for sending inband loopback
commands and for sending/receiving test signals (QRSS, etc.).
Use the CSU Configuration menu to select a specific loopback/test
mode. CSU Configuration menu, Item A, Choice 1, Full T1 testing
mode must be selected if you are using full T1 loopbacks or test
signals. Choices 2 and 3 are the drop and insert choices; Choice 2 =
DSO testing at n x 56kbs; Choice 3 = DSO testing at n x 64kbs.
When you select either choice 2 or 3 (for DSO loopbacks/tests), an
additional menu selection is provided (Item “D”) to select one or
more DSO channels. Select channels (1-24) using menu item “D.”