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Features Description 2-103
The Series II sends ringing to the called station by automatically performing the
following operations:
•
Activates interface isolation to open circuit tip (pin 5) and ring (pin 4)
from the 2-wire to 4-wire hybrid circuit.
•
Disconnects the programmable loop current generator.
•
Connects the positive potential of the bias voltage to the tip conductor for
positive ringing polarity, or to the ring conductor for negative ringing.
•
Connects the AC ringing signal with a negative bias potential to the ring
conductor for positive ringing polarity, or to the tip conductor for negative
ringing.
In 2-wire switched configuration the Series II will automatically disconnect
ringing (trip ringing) when it detects 10 mA or more of DC current flow from the
bias voltage source. The telephone or DCE generates a path for DC current flow
when it makes an on-hook (high DC impedance) to off-hook (low DC impedance)
transition to answer the call.
The Series II performs ring trip at the called station by automatically performing
the following operations:
•
Disconnects ringing generator from tip (pin 5) and ring (pin 4).
•
Deactivates interface isolation to connect tip (pin 5) and ring (pin 4) to the
2-wire to 4-wire hybrid circuit. Interface isolation will not be deactivated if
the station interface has been explicitly configured for isolation (see
Interface Isolation section of manual).
•
Connects the programmable loop current generator.