XRT73LC00A_08 Datasheet, PDF (38/63 Pages) Exar Corporation – E3/DS3/STS-1 LINE INTERFACE UNIT

REV. 1.0.1
XRT73LC00A
E3/DS3/STS-1 LINE INTERFACE UNIT
Template requirements. For the XRT73LC00A this is achieved by setting the TXLEV input pin or bit-field to
the appropriate level.
When the System Manufacturer is interfacing the Receive Section of the XRT73LC00A to the Cross-Connect,
they should keep aware of the following facts:
1. All DS3 or STS-1 line signals that are present at either the DSX-3 or the STSX-1 Cross-Connect are
required to meet the Isolated Pulse Template Requirements per Bellcore GR-499-CORE for DS3 applica-
tions or Bellcore GR-253-CORE for STS-1 applications.
2. Bellcore documents state that the amplitude of these pulses at the DSX-3 or STSX-1 can range in ampli-
tude from 360mVpk to 850mVpk.
3. Bellcore documents stipulate that the Receiving Terminal must be able to receive this pulse-template com-
pliant line signal over a cable length of 0 to 450 feet from the DSX-3 or the STSX-1 Cross Connect.
These facts are reflected in Figure 17.
FIGURE 17. THE TYPICAL APPLICATION FOR THE SYSTEM INSTALLER
Transmitting
Terminal
0 to 450 feet of
Cable
Digital Cross-
Connect System
DSX-3
or
STSX-1
Pulses that are
compliant to the
Isolated DSX-3 or
STSX-1 Pulse
Template
Requirement
0 to 450 feet of
Cable
Receiving
Terminal
Design Considerations for DS3 and STS-1 Applications
When installing equipment into environments as depicted in Figure 18, the system installation personnel may
be able to determine the cable length between the local terminal equipment and the DSX-3/STSX-1 Cross-
Connect Patch-Panel. The cable length between the local terminal equipment and the DSX-3/STSX-1 Cross-
Connect Patch Panel ranges between 0 and 450 feet.
It is extremely unlikely that the system installation personnel will know the cable length between the DSX-3/
STSX-1 Cross-Connect Patch-Panel and the remote terminal equipment. We recommend that the Receive
Equalizer be enabled by setting the REQDIS input pin or bit-field to "0".
33