XRT59L921 Datasheet, PDF (20/32 Pages) Exar Corporation – TWENTY-ONE CHANNEL E1 LINE INTERFACE UNIT

XRT59L921
TWENTY-ONE CHANNEL E1 LINE INTERFACE UNIT
FIGURE 6. ILLUSTRATION OF THE ITU-T G.703 PULSE TEMPLATE FOR E1 APPLICATIONS
269 ns
(244 + 25)
V = 100%
194 ns
(244 – 50)
Nominal pulse
REV. 1.2.1
50%
0%
244 ns
219 ns
(244 – 25)
488 ns
(244 + 244)
Note – V corresponds to the nominal peak value.
Each channel (within the XRT59L921) will take each mark (which is provided to it via the Transmit Input
Interface block, and will generate a pulse that complies with the pulse template, presented in Figure 6, (when
measured on the secondary-side of the Transmit Output Transformer).
1.4 Interfacing the Transmit Sections of the XRT59L921 to the Line
ITU-T G.703 specifies that the E1 line signal can be transmitted over coaxial cable and terminated with 75Ω or
transmitted over twisted-pair and terminated with 120Ω. However, in both applications (e.g., 75Ω or 120Ω), the
user is advised to interface the Transmitter to the Line, in the manner as depicted in Figure 7 and Figure 8,
respectively.
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