Patton electronic 2710 - Manual (Page 35)

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5.2 LOOP (V.54 & TELCO) DIAGNOSTICS
The NetLink-T1™ offers three V.54 loop diagnostics and is compatible
with two Telco loop diagnostics. Use these diagnostics to test the CSU/
DSU and any communication links. These tests can be activated via the
software control port (See “System Diagnostics” on page 23 or via sig-
nals on the serial port interface.
Operating Local Loopback (LL)
The Local Loopback (LL) test checks the operation of the local NetLink-
T1™, and is performed separately on each unit. Any data sent to the
local NetLink-T1™ in this test mode will be echoed (returned) back to the
user device (i.e., characters typed on the keyboard of a terminal will
appear on the terminal screen).
To perform a LL test, follow these steps:
1. Activate LL. This may be done in one of three ways:
— Enter Local Loop from the System Diagnostics/Statistics
menu and toggle the until “LL” appears next to the
Local Loop option.
— Activate the “LL” signal on the DTE. If you are not sure which
lead is the “LL” signal, please refer to Appendix D.
2. Verify that the data terminal equipment is operating properly and
can be used for a test.
3. Perform a V.52 BER (bit error rate) test as described in Section 5.3.
If the BER test equipment indicates no faults, but the data terminal
indicates a fault, follow the manufacturer’s checkout procedures for
the data terminal. Also, check the interface cable between the ter-
minal and the NetLink-T1.
Operating Remote Digital Loopback (RL)
The Remote Digital Loopback (RL) test checks the performance of both
the local and remote NetLink-T1™, as well as the communication link
between them. Any characters sent to the remote NetLink-T1™ in this
test mode will be returned back to the originating device (i.e, characters
typed on the keyboard of the local terminal will appear on the local termi-
nal screen after having been passed to the remote NetLink-T1™ and
looped back).