XRT75R12 Datasheet, PDF (78/89 Pages) Exar Corporation – TWELVE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH JITTER ATTENUATOR

XRT75R12
REV. P1.0.2
PRELIMINARY
TWELVE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH JITTER ATTENUATOR
BIT NUMBER
2
NAME
TAOS
1
TxCLKINV
0
TxLEV
TYPE
DESCRIPTION
R/W Transmit All OneS Pattern - Channel_n:
This READ/WRITE bit-field is used to command the Transmit Section
of Channel_n to generate and transmit an unframed, All Ones pattern
via the DS3, E3 or STS-1 line signal (to the remote terminal equip-
ment).
Whenever the user implements this configuration setting, the Transmit
Section will ignore the data that it is accepting from the System-side
equipment and output the "All Ones" Pattern.
0 - Configures the Transmit Section to transmit the data that it accepts
from the System-side Interface.
1 - Configures the Transmit Section to generate and transmit the
Unframed, All Ones pattern.
R/W Transmit Clock Invert Select - Channel_n:
This READ/WRITE bit-field is used to select the edge of the TxCLK_n
input that the Transmit Section of Channel_n will use to sample the
TxPOS_n and TxNEG_n input pins, as described below.
0 - Configures the Transmit Section (within the corresponding channel)
to sample the TxPOS_n and TxNEG_n input pins upon the falling edge
of TxCLK_n.
1 - Configures the Transmit Section (within the corresponding channel)
to sample the TxPOS_n and TxNEG_n input pins upon the rising edge
of TxCLK_n.
NOTE: This is done on a per-channel basis.
R/W Transmit Line Build-Out Select - Channel_n:
This READ/WRITE bit-field is used to enable or disable the Transmit
Line Build-Out (e.g., pulse-shaping) circuit within the corresponding
channel. The user should set this bit-field to either "0" or to "1" based
upon the following guidelines.
0 - If the cable length between the Transmit Output (of the correspond-
ing Channel) and the DSX-3/STSX-1 location is 225 feet or less.
1 - If the cable length between the Transmit Output (of the correspond-
ing Channel) and the DSX-3/STSX-1 location is more than 225 feet .
The user must follow these guidelines in order to insure that the Trans-
mit Section (of Channel_n) will always generate a DS3 pulse that com-
plies with the Isolated Pulse Template requirements per Bellcore GR-
499-CORE, or an STS-1 pulse that complies with the Pulse Template
requirements per Telcordia GR-253-CORE.
NOTE: This bit-field is ignored if the channel has been configured to
operate in the E3 Mode.
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