Paradyne 7510 DSU - Manual (Page 34)

Testing
5-2 7510-A2-GB20-10 November 1997
Loopbacks can be started from a variety of points in the network, as shown in
Table 5-1.
Table 5-1. Device Messages
Loopback Type Initiated By Notes
Bilateral Loopback H User
H Remote unit sending
V.54 sequence
When enabled, running a DSU loopback
also automatically starts a local
loopback. Refer to Table A-3,
Data Port
Options , to enable.
CSU Loopback H User (Network tests)
H DDS Network, by
loop current reversal
When initiated by the network, CSU
Loopback cannot be disabled by the
user.
DSU Loopback
(Digital) H User Refer to Table A-3, Data Port Options .
Local Loopback H User
H DTE via CT141
Control via CT141 can be disabled.
Refer to Table A-3,
Data Port Options .
Network-initiated
56 kbps DSU
Loopback (Non-
latching loopback) H DDS Network Cannot be disabled by user.
Network-initiated
64 kbps CC DSU
Loopback
(Latching loopback) H DDS Network Includes optional data scrambling and
uses 25-second timer to detect the
network sequence. Can be disabled by
user.
Remote Digital
Loopback H Remote unit sending
V.54 sequence Same as a DSU Loopback but initiated
by a remote unit via V.54 sequence.
Can be disabled locally. Refer to
Table A-2,
Network Interface Options .
V.54 Sequences to
remote unit H User
H DTE via CT140
Control via CT140 can be disabled.
Refer to Table A-3,
Data Port Options .