Nortel DMS-100 Series Maintenance Manual page 393

pathways to the loop. The attempt to run the silent switchman test causes a
of the reorder tone to return to the RCS line.
The same relay cuts the line card off from the subscriber loop. The test pair
that comes from the MTA switch accesses the subscriber loop.
Four types of passive termination are provided in the RCS:
Absorb—A 900 Ω resistor connects between the tip and ring of the line
card circuit. This termination causes the absorption of an incoming
signal.
The termination is set up when the SMS sends the RCS the A- and B-bit
pattern to ring a ring party. The ring party must have positive dc voltage
in a superimposed ringing, multi-party line circuit.
Reflect—A loop connects between the tip and ring of the line card
circuit. The tip and ring are shorted together. This termination causes
the reflection of an incoming signal.
The termination is set up when the SMS sends the RCS an A- and B-bit
pattern to ring in the following condition. The A- and B-bit pattern rings
a ring party with negative dc voltage in superimposed ringing,
multi-party line circuit. The termination is set up in the following
condition also. The SMS sends the A- and B-bit pattern to ring a
single-party or coin line.
Absorb-PTPG—This termination is the same as the absorb termination,
except that a positive tip party ground (PTPG) is provided. Detection of
a dc path to ground occurs if the RCS provides a positive dc voltage to
the tip or ring.
The termination is set up when the SMS sends the RCS the A- and B-bit
pattern. The bit pattern causes the ringing of a tip party with positive dc
voltage in a superimposed ringing, multi-party line circuit. This
termination is set up in the following condition also. The SMS sends the
A- and B-bit pattern to execute coin collect for a coin card.
Reflect-NTPG—This termination is the same as the reflect termination,
except that a negative tip party ground (NTPG) is provided. This is a dc
path to ground detected if the RCS provides a negative dc voltage to the
tip or ring.
The termination is set up when the SMS sends the RCS the A- and B-bit
pattern. The bit pattern causes ringing of a tip party with negative dc
voltage in a superimposed ringing, multi-party line circuit. This
termination is set up in the following condition also. The SMS sends the
A- and B-bit pattern to execute coin return for a coin card.
DMS-100 Family SMS Maintenance Manual XPM10 and up
Trouble isolation and correction 9-29