NT5K17 Direct Dialing Inward Trunk Card 1-7
UK Trunk cards description 553-3001-173
Far End Release
The public exchange disconnects the call by sending a forward clear signal.
The forward clear signal is a high impedance loop (8.5K ohms or greater)
in the direction of the DDI unit.
When the DDI unit detects the high impedance loop, it sends a change of
state message to the CPU. If this state lasts for greater than 150 ms, the
CPU will send a release acknowledgement message to the DDI unit. The
DDI unit will respond by returning to the idle state.
Near End Release
When the Meridian 1 disconnects the call, the CPU sends a message to the
DDI unit, which in turn will respond by returning to the idle state.
When the public exchange detects the idle state, it restores the high
impedance loop on the A and B wires. The CPU interprets the high
impedance loop as a release acknowledgement signal from the public
exchange.
Backward Busy or Disabled
When a DDI unit is busy or disabled and cannot accept a call, it sends a
backward busy signal to the public exchange. In this state, both battery and
ground are removed from the A and B wires.
United Kingdom
United Kingdom
United Kingdom
United Kingdom
United Kingdom
United Kingdom
