XRT86VL38
PRELIMINARY
xr
OCTAL T1/E1/J1 FRAMER/LIU COMBO
REV. P1.0.6
307
4.0
GENERAL DESCRIPTION AND INTERFACE
The XRT86VL38 supports multiple interfaces for various modes of operation. The purpose of this section is to
present a general overview of the common interfaces and their connection diagrams. Each mode will be
described in full detail in later sections of the datasheet.
N
OTE
: For a brief tutorial on Framing Formats, see Appendix A in the back of the datasheet.
4.1
Physical Interface
The Line Interface Unit generates/receives standard return-to-zero (RZ) signals to the line interface for T1/E1/
J1 twisted pair or E1 coaxial cable. The physical interface is optimized by placing the terminating impedance
inside the LIU. This allows one bill of materials for all modes of operation reducing the number of external
components necessary in system design. The transmitter outputs only require one DC blocking capacitor of
0.68
µ
F and a 1:2 step-up transformer. The receive path inputs only require one bypass capacitor of 0.1
µ
F
connected to the center tap (CT) of the transformer and a 1:1 transformer. The receive CT bypass capacitor is
required for Long Haul Applications, and recommended for Short Haul Applications. Figure 12 shows the
typical connection diagram for the LIU transmitters. Figure 13 shows a typical connection diagram for the LIU
receivers.
F
IGURE
12. LIU T
RANSMIT
C
ONNECTION
D
IAGRAM
U
SING
I
NTERNAL
T
ERMINATION
F
IGURE
13. LIU R
ECEIVE
C
ONNECTION
D
IAGRAM
U
SING
I
NTERNAL
T
ERMINATION
T
TIP
T
RING
XRT86VL38 LIU
1:2
Internal Impedance
Line Interface T1/E1/J1
C=0.68uF
One Bill of Materials
Transmitter
Output
R
TIP
R
RING
XRT86VL38 LIU
1:1
Internal Impedance
Line Interface T1/E1/J1
One Bill of Materials
Receiver
Input
0.1
µ
F