NTD12 Dual-port DTI/PRI card description and installation Page 141 of 188
ISDN PRI Installation
Receiver Impedance
A per trunk set of four DIP switches provides selection between 75, 100 or
120
Ω
values.
Table 37 - Trunk interface receiver impedance switch settings
Ring ground switches
A set of four DIP switches selects which Ring lines are connected to ground.
Table 38- Ring ground switch settings
Description
S8/S14 Switch Setting
75
Ω
OFF
OFF
ON
OFF
100
Ω
ON
OFF
OFF
ON
120
Ω
OFF
OFF
OFF
ON
Switch
Description
S2 Switch Setting
1
Trunk 0 Transmit
OFF - Ring line is not grounded
ON - Ring line is grounded
2
Trunk 0 Receive
OFF - Ring line is not grounded
ON - Ring line is grounded
3
Trunk 1 Transmit
OFF - Ring line is not grounded
ON - Ring line is grounded
4
Trunk 1 Receive
OFF - Ring line is not grounded
ON - Ring line is grounded