Nortel Circuit Card Installation Manual page 750

Page 750 of 906
553-3001-211 Standard 3.00
NTAK79 2.0 Mb PRI card
Switch SW1 – DCHI Configuration
This switch enables/disables the on-board DCHI and sets the operating mode
of the DCHI. DPNSS1 mode is not supported at this time. For all other
countries that do not use DPNSS, use Q.931 mode.
Table 240
Switch SW1
Switch
SW 1-1
SW 1-2
Switch SW2 – Carrier Impedance Configuration
This switch sets the carrier impedance to either 120 ohms or 75 ohms.
Twisted pair cable is usually associated with 120 ohms. Coaxial cable is
usually associated with the 75 ohms setting.
Table 241
Switch SW2
Cable Type
75 ohms
120 ohms
Switch SW3 – Clock Controller Configuration
This switch enables/disables (H/W) the on-board Clock Controller. Disable
the SW 3-2 if the on-board clock controller is not in use.
Table 242
Switch SW3
Switch
SW 3-1
SW 3-2
August 2005
Down (On)
enable DCHI
DPNSS1/DASS2
SW 2-1
Up (Off)
Down (On)
Down (On) Up (Off)
— —
Disabled Enabled
Up (Off)
disable DCHI
Q.931
SW 2-2
Down (On)
Up (Off)
Note
Spare