XRT59L921 Datasheet, PDF (29/32 Pages) Exar Corporation – TWENTY-ONE CHANNEL E1 LINE INTERFACE UNIT

REV. 1.2.1
APPLICATION INFORMATION
XRT59L921
TWENTY-ONE CHANNEL E1 LINE INTERFACE UNIT
Figure 17 and Figure 18, provide example schematics on how to interface Channel 1 of the XRT59L921 to the
line, under the following conditions.
• Receiver is Transformer-coupled to a 75Ω unbalanced line.
• Receiver is Transformer-coupled to a 120Ω balanced line.
FIGURE 17. ILLUSTRATION ON HOW TO INTERFACE CHANNEL 1 (OF THE XRT59L921) TO THE LINE (RECEIVER IS
TRANSFORMER-COUPLED TO A 75Ω UNBALANCED LINE)
XRT59L921
TTIP_x
TxPOS_x
TxPOS_x
9.1 Ω
1:2
TxNEG_x
TxNEG_x
TxLineClk_x
TxLineClk_x
TRING_x
9.1 Ω
RxPOS_x
RxNEG_x
Loss Of Signal_x
RxPOS_x
RTIP_x
RxNEG_x
RxLOS_x
RRING_x
1:1
75 Ω
27