Rainbow Electronics DS26502 - Manual (Page 77)

DS26502 T1/E1/J1/64KCC BITS Element
77 of 125
13. LINE INTERFACE UNIT (LIU)
The LIU in the DS26502 contains three sections: the receiver, which handles clock and data recovery; the
transmitter, which 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 DS26502 can switch between T1 or E1 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 DS26502, using a fixed 120Ω external termination, can connect to T1, J1, E1,
64KCC, or 6312K 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.
Figure 13-1. Basic Network Connection
TTIP
TRING
RTIP
RRING
DS26502
TRANSMIT
LINE
RECEIVE
LINE
10 mF
60 60
0.01 mF
BACKPLANE
CONNECTIONS
1:1
2:1