CANOGA PERKINS 2346 T3 Fiber Optic Modem - Manual (Page 29)

EdgeAccess Universal Chassis System
2346 T3 Modem 4-5
Loopback
Use loopback to diagnose a fault on the optical link, either on a modem or with a cable. The 2346
supports both local and remote loopback in one or both directions. Set loopback either in software for
a managed 2346 or at the loopback function switch on a standalone enclosure See Figures 4
through 9.
• Local loopback returns the received electrical signal to the local site and ignores the received
optical signal; turn on Local Loopback at the local modem. The remote modem returns All Ones
to the remote site. Faulty data can indicate that the local 2346 is faulty.
• Remote loopback returns the received optical signal to the remote modem and ignores the
received electrical signal; turn on Remote Loopback at the local modem. The remote modem
returns All Ones to the remote site. Faulty data can indicate that either the fiber optic cable link
or the remote 2346 is faulty.
• Bi-directional loopback returns the received electrical signal to its local site and the received
optical signal to the modem that sent it; turn on Local loopback at one modem and Remote
Loopback at the other modem. Faulty data can isolate the faulty equipment to indicate that either
the fiber optic link or a 2346 is faulty.
To set up the software and start or stop loopback, follow these steps:
1. From the Main Menu, type 1 , "System Configuration," and press <Enter>.
2. At the System Configuration menu, type 2 , "Functional Configuration," and press <Enter>. The
Functional Configuration screen appears.
3. Enable Software Override, if needed. Type 1 and press <Enter>, then press <Space> to cycle
between Enabled and Disabled, and press <Enter> to select Enabled. To move to the next
column for a remote modem, press <Tab>.
4. To set and start Loopback, type 3 and press <Enter>, then press <Space> to cycle through the
options. To move to the next column for a remote modem, press <Tab>. When you finish
making selections, press <Enter>; loopback starts.
5. To stop Loopback, type 3 and press <Enter>, then press <Space> to cycle to Norm. To move to
the next column for a remote modem, press <Tab>. When you finish making selections, press
<Enter>; loopback ends.
6. To return to the Main Menu, press <Esc>.
Alternately, if the 2346 is in a standalone enclosure that includes loopback support, such as a 1020,
you can set the Loopback function switch on the front panel for local or remote loopback; for details,
see the manual for the enclosure.