Remote Digital Loopback - Paradyne 3610 Application Manual

COMSPHERE 3600 Series Data Service Units

Remote Digital Loopback

Remote Digital Loopback (RL) is typically used to
support testing by an external device, such as a protocol
analyzer connected to the local DSU's DTE interface. A
test message from the external device is looped back from
the receiver to the transmitter in the remote DSU and
returned to the local DSU (Figure 5-8).
In Remote Digital Loopback, the local DSU (control
or tributary) or the 6700 or 6800 Series NMS places the
remote DSU into Digital Loopback. A control DSU can
originate Remote Digital Loopback in a point-to-point or
multipoint network; a tributary DSU can only originate
Remote Digital Loopback in a point-to-point network.
When a control or tributary DSU originates Remote
Digital Loopback, both originating and targeted DSUs
enter Test mode. On a multipoint circuit, all tributaries are
placed in Test mode. No other test can be run at the
originating DSU or the targeted DSU until the Remote
Digital Loopback is aborted.
5-22
session-disruptive except when a dial backup session is
active and used to determine whether a control DSU, a
single tributary, and the network between them are
functioning properly. This requires a network connection
to both DSUs. However, a DTE connection to the remote
DSU is not required.
disruptive when the DBM is in Dial Backup mode and
nondisruptive when in Standby mode. A DTE connection
to the remote DBM is not required.
Figure 5-8. Remote Digital Loopback
July 1999
NOTE
To abort the Remote Digital
Loopback, issue the Abort
command to the control
DSU-DBM, not the tributary.
For a DSU, Remote Digital Loopback is
For a DBM, Remote Digital Loopback is session-
3610-A2-GB41-70