ADTRAN 1200410L2, Руководство пользователя

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Chapter 5. Configuration Menu
61200410L2-1A ESU LT User Manual 43
In CAS mode, there are 30 channels available for user data. If
timeslot 16 is included in the unit’s mapping, it will be disregarded.
For example, if the starting TS0 is set to 1 and the number of TS0s
is set to 20, user data will be mapped to timeslots 1 to 15 and 17 to
21.
UNFRAMED
The ESU LT can operate in unframed mode. In this mode, user data
is inserted into all 32 channels of the E1 stream. Since the object of
running without framing is to utilize the full bandwidth of the E1
line, the starting TS0 and number of TS0s option settings are
ignored.
Other option settings that have no effect in unframed mode include:
CRC4
,
NFAS W
ORD
,
RFA G
EN
,
A
UTO
DTE TX CLK
,
M
APPING
,
D
ATA
I
NVERT
,
I
NBAND
.
Choices:
CCS
;
CAS/TS16
;
U
NFRAMED
Line Code
Selects either Alternate Mark Inversion (
AMI
) or High Density
Bipolar Order 3 (
HDB3
) line coding.
AMI
provides a 12.5%
minimum ones pulse density and alternates signal polarity of
transmitted ones from positive to negative.
HDB3
is an extension
of
AMI
that inserts a bipolar violation (signal of the wrong polarity)
whenever there are 4 or more transmitted zeros.
Choices:
HDB3
;
AMI
CRC-4
When enabled, the CRC-4 checksum bits are transmitted in the
outgoing E1 data stream. The received signal is also checked for
errors. CRC-4 can be enabled in both CCS and CAS modes. A
CRC-4 checksum cannot be sent in unframed mode.
Choices:
E
NABLE
;
D
ISABLE
NFAS Word
If enabled, the network interface receiver requires the NFAS word
(time slot 0 in odd frames) and the FAS word
(time slot 0 in even frames) for frame sync. When disabled, only
the FAS word is needed for frame sync.
Choices:
E
NABLE
;
D
ISABLE