ds26518 Maxim Integrated Products, Inc., ds26518 Datasheet - Page 80

• Manufacturer Part Number: ds26518
• Description: 8-port T1/e1/j1 Transceiver
• Manufacturer: Maxim Integrated Products, Inc.

DS26518 8-Port T1/E1/J1 Transceiver
9.12
Line Interface Units (LIUs)
The DS26518 has eight identical LIU transmit and receive front-ends for each of the eight framers. Each LIU
contains three sections: the transmitter, which waveshapes and drives the network line; the receiver, which handles
clock and data recovery; and the jitter attenuator. The DS26518 LIUs can switch between T1 or E1 networks
without changing any external components on either the transmit or receive side.
Figure 9-19
shows a
recommended circuit for software selected termination with protection. In this configuration the device can connect
to 100: T1 twisted pair, 110: J1 twisted pair, 75: or 120: E1 twisted pair without additional component changes.
The signals between the framer and LIU are not accessible by the user, thus the framer and LIU cannot be
separated. The transmitters have fast high-impedance capability and can be individually powered down.
The DS26518’s transmit waveforms meet the corresponding G.703 and T1.102 specifications. Internal software-
selectable transmit termination is provided for 100: T1 twisted pair, 110: J1 twisted pair, 120: E1 twisted pair
and 75: E1 coaxial applications. The receiver can connect to 100: T1 twisted pair, 110: J1 twisted pair, 120: E1
twisted pair, and 75: E1 coaxial. The receive LIU can function with a receive signal attenuation of up to 36dB for
T1 mode and 43dB for E1 mode. The receiver sensitivity is programmable from 12dB to 43dB of cable loss. Also a
monitor gain setting can be enabled to provide 14dB, 20dB, 26dB, and 32dB of resistive gain.
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