Instruction Manual

DS26504 T1/E1/J1/64KCC BITS Element
79 of 128
13. LINE INTERFACE UNIT (LIU)
The LIU in the DS26504 contains three sections: the receiver, which handles clock and data recovery; the
transmitter, which generates waveshapes and drives the network line; and the jitter attenuator. These three
sections are controlled by the line interface control registers (LIC1–LIC4), which are described below.
The DS26504 can switch among T1, E1, and 64KCC networks without changing any external
components on either the transmit or receive side. Figure 13-1 shows a network connection using
minimal components. In this configuration the DS26504, using a fixed 120Ω external termination, can
connect to T1, J1, E1, 64KCC, or 6312kHz without any component change. The receiver can adjust the
120Ω termination to 100Ω, 110Ω, or 75Ω. The transmitter can adjust its output impedance to provide
high return loss characteristics for 75Ω, 100Ω, 110Ω, and 120Ω lines. Other components may be added to
this configuration to meet safety and network protection requirements. This is covered in the
Recommended Circuits section (Section 13.8).
Figure 13-1. Basic Network Connection
TTIP
TRING
RTIP
RRING
DS26504
TRANSMIT
LINE
RECEIVE
LINE
1
m
F
60 60
0.01mF
BACKPLANE
CONNECTIONS
1:1
2:1