Carrier Interface; Carrier Grounding - Meridian Nortel 1 Option 11C Technical Reference Manual

Carrier interface

For the E-1 interface, the connection to the external digital carrier is provided
by the line interface chip. This device provides accurate pulse shaping to meet
the CCITT pulse mask requirements. It provides clock recovery functions on
the receive side as well as tolerance to jitter and wander in the received bit
stream.
Impedance matching (Switch SW2)
The line interface provides for the use of either 75ohm coaxial or 120ohm
twisted pair cable. The impedance is selected by SW2, as shown in the
settings table below.
Table 155
Impedance matching switch settings
Note: The ON position for all the switches is towards the bottom of the
card. This is indicated by a white dot printed on the board adjacent to the
bottom left corner of each individual switch.

Carrier grounding

NTBK50 provides for the capability of selectively grounding the shield of the
Tx and/or Rx pairs of the carrier. Closing (down) the on-board switch will
apply FGND to the appropriate carrier cable shield. The switch settings are
shown below.
NTBK50 2.0 Mb PRI card
Cable Type
75¾
120¾
Option 11C and 11C Mini
Page 499 of 544
SW 2-1
Down (On)
Up (Off)
Technical Reference Guide