Nortel Meridian 1 Option 11C, Administration And Maintenance

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Page 444 of 492 Appendix A — 2Mb PRI implementation
553-3011-311 Standard 7.0 May 1999
Set the switches found on the circuit card as per the requirements of your
specific installation:
Switch SW1—DCHI Configuration (NTAK93 only)
This switch enables/disables the DCHI and sets the operating mode of the
DCHI. It is only used if an NTAK93 D-channel handler daughterboard is
being used. It has no effect when using the NTBK51 DDCH daughterboard.
For the U.K., use DPNSS1 mode. For all other countries, use Q.931 mode.
Switch SW2—Carrier Impedance Configuration
This switch sets the carrier impedance to either 120¾ or 75¾. Twisted pair
cable is usually associated with 120¾. Coaxial cable is usually associated
with the 75¾ setting.
Switch SW4—Carrier Shield Grounding
This switch allows for the selective grounding of the Tx and/or Rx pairs of
the carrier cable. Closing the switch (down position) applies Frame Ground
(FGND) to the coaxial carrier cable shield, creating a 75¾ unbalanced
configuration. This applies only to the NTBK05CA cable.
Note: The usual method is to ground the outer conductor of the receive
coax signal.
Switch Down (On) Up (Off)
SW 1-1 — —
SW 1-2 DPNSS1/DASS2 Q.931
Cable Type SW 2-1 SW 2-2
75¾ Down (On) Down (On)
120¾ Up (Off) Up (Off)
Switch Down (On) Up (Off)
SW 4-1 Rx—FGND Rx—OPEN
SW 4-2 Tx—FGND Tx—OPEN