Nortel Networks 553-3001-211 Loop start operation

Page 782 of 894 NTCK16 Generic Central Office Trunk cards
553-3001-211 Standard 2.00 September 2004
• provide 4 dB dynamic attenuation pads on a per call basis
• allow individual units or the entire board to be disabled by software
• provide software selectable A-law or µ-law companding
• indicate self-test status during an automatic or manual self-test
• provide card-identification for auto configuration, and for determining
the serial number and firmware level of the card
• convert transmission signals from analog-to-digital and from
digital-to-analog
• provide termination and trans-hybrid balance impedance to match
600 Ω.
Operation
Each NTCK16AX and NTCK16BX generic Central Office trunk card
supports the following:
• Loop start operation
• Battery reversal detection
• Busy tone detection and supervision
• Loss Switching
• Trunk-to-Trunk connections
• Call Disconnect
In addition, the NTCK16AX circuit card supports internal 12/16 kHz PPM
detection.
Loop start operation
Loop start operation is configured in software and is implemented in the card
through software download messages.
Idle state
In the idle state, the ringing detector is connected across the tip and ring wires,
providing a high impedance loop toward the Central Office.