V.35 Fiber Modem Installation and Operation Manual
Page 11 of 13
Local Loopback Schematic
S5.6: local digital loopback control (DLOOP). “OFF” indicates normal operation;
“ON” indicates local digital loopback. The default is “OFF”. With a loopback
from local V.35 interface to E1 optic interface, it is used for testing whether the
remote device and E1 optic line are in normal operation.
Local Digital Loopback
S5.7
:“OFF”indicates normal operation
；
“ON”indicates command remote loopback.
The default is “OFF”. As this command must be sent through E1 optic line to
remote end for validness, it will become invalid at the following two cases:
①
the remote end is not V.35 Fiber Modem device;
②
V.35 Fiber Modem is
working at a non-framing status, at this moment all time slots of E1 are used
for transmitting the data from V.35 interface at a rate of 2048Kbps. Through a
transmission of loopback command from local device to remote device, the
command remote loopback is achieved.
Remote Loopback
S5.8: Pseudo-
random code test control (PATT). “OFF” indicates normal operation;
“ON” indicates pseudo-random sequence test. The default is “OFF”. It
generates a pseudo-random sequence code to be transmitted to V.35 optic
line output terminal and tests whether V.35 optic line input signal is in
compliance with this sequence standard, so as to judge whether the device
and line transmission have an error code.
pseudo-random Code Test
Remark:
Pseudo-random sequence code test can be made only under a
V.35
Fiber Modem V35
Optical
Interface
Fiber Modem V35
Optical
Interface
V.35
Fiber Modem V35
V.35
V.35
Fiber Modem V35
Fiber Link
Remote
Local
V.35
V.35
Fiber Modem V35
Fiber Modem V35
Local
Remote
Fiber Link
