Page430 of 544 NT1R20Off Premise Station (OPS) analog line card
553-3011-100 Standard14.00 January 2002
Table 1 34
Call connection sequence—near-end station receiving call
State Signal/Direction
Far-endNear-end Remarks
Line card unit idle Group on tip, battery on ring
High resistance loop
No battery current drawn.
Far-end station goes off-hook and
addresses (dials-up) the near-end
station. The Option 11C receives the
incoming call on a trunk and determines
the TN.
Incoming call Ringing Option 11C applies 20 Hz ringing to ring
lead.
Near-end station
off-hook
Low resistance loop
Two-way voice
connection
Option 11C detects increase in loop
current, tips ringing, and puts call through
to near-end station.
Near end station
hangs up first
High-resistance loop If near end station hangs-up first, the line
card detects the drop in loop current.
Line card unit idle Group on tip, battery on ring
High resistance loop
Line card unit is ready for the next call.
Far end station
hangs up first
High resistance loop If the far-end hangs-up first, Option 11C
detects disconnect signalling from the
trunk. The person at the near-end
recognizes the end of the call and hangs-
up.
Line card unit idle Ground on tip/battery on ring
High resistance loop
Line card unit is ready for the next call.