ADTRAN 1212010, User Manual

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61212016L1-20 NT1 T400 User Manual B-1
Appendix B
S/T Bus Configurations
SHORT PASSIVE BUS
The short passive bus configuration allows the connection of up to
eight TEs at any point on the bus. The bus length is limited to 600 feet,
as illustrated in Figure B-1.
To select this bus configuration, set switch 1-2 to the Short position.
The bus termination resistors (TRs) can be placed at any point along
the bus. If the TEs have internal TRs that can be optioned, only one
TE's TRs should be enabled. The TRs in the NT1 Type 400 are enabled
by setting switches 1-3 and 1-4 to the ON position, and switches 1-5
and 1-6 to the OFF position. If the unterminated TEs are placed within
20 feet of the NT1, set switches 1-3 and 1-4 to the OFF position, and
switches 1-5 and 1-6 to the ON position. The switch settings should al-
ways be maintained, unless an external 100
Ω
resistor is being used. If
an external TR is used, set switches 1-3 through 1-6 to the OFF posi-
tion.
Figure B-1. Short Passive Bus Configuration
TR TR* NT1
TE TE TE
* Is not needed if NT1Õs
TR
is used
600
FEET