9
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
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