Pad Switching; Trunk Types Description; Ground Start Operation - Northern Telecom NT5K17 Description

PAD switching

Trunk types description

Ground start operation

United Kingdom United Kingdom United Kingdom
United Kingdom United Kingdom United Kingdom
The transmission properties of each trunk are characterized by the class-of-
service (COS) assigned in the trunk data block (LD 14).
• PADs should be switched OUT when connecting to "long line"
(0-8 dB) public exchange trunk interfaces.
(COS = LOL)
• PADs may be switched IN when connecting to "short line" (0-6 dB)
public exchange trunk interfaces.
(COS = SHL)
Each NT5K18 Exchange Line trunk card unit is capable of operating as
one of the following:
• Exchange line - Ground Start
• Exchange line - Loop Start with Loop Disconnect Clear Release
• Exchange line - Loop Start with Loop Guarded Release
In addition, all exchange line types support Periodic Pulse Metering
(PPM), or Subscriber Pulse Metering (SPM), as it is sometimes called.
For information on features and signalling arrangements, see Generic X11
including supplementary features (PO730484 or NTCK09 in the UK).
Ground start operation is configured in software and implemented through
software download messages.
Idle State
In the idle state, the A wire from the Public Exchange is open and a high
resistance potential is present on the A wire of the trunk. The A wire is
monitored for the application of ringing from the Public Exchange.
Call placed by Public Exchange
The Public Exchange places a call by applying ringing to the A wire. The
Exchange Line Trunk card scans for ringing detection before presenting the
call to an attendant and tripping the ringing. A low resistance is placed
across the A and B wires and a speech path is established.
NT5K18 Exchange Line Trunk Card 2-5
UK Trunk cards description 553-3001-173