Port Type Definition - Nortel Meridian 1 Succession 1000 Manual

For BRIT, switching of loss values occurs in the receive and transmit
directions. The applied losses depend on the port type involved in the
connection with the BRIL.

Port type definition

The following criteria identify the port types involved in a connection:
• unit type
• Class of Service (CLS)
• Port type (PTYP) designation in LD 16
• Trunk Signaling
• XTRK type
The trunk data block Class of Service (CLS) assignment characterizes the
transmission properties of each trunk. The options in a North American
context are
• Via Net Loss (VNL)
• Non-VNL, either
Transmission Compensated (TRC)
or Non-Transmission Compensated (NTC)
Assignment of CLS VNL or non-VNL ensures stability and minimizes echo
on long-haul connections, 4-wire TIE, and CCSA. Similarly, assignment of a
non-VNL CLS applies to 2-wire TIE, COT, FEX, WAT, CCSA, and
4-wire non-VNL facilities. The non-VNL CLS options in a North American
context are
• TRC — 2-wire non-VNL trunk facility with a loss of greater than
• NTC — 2-wire non-VNL trunk facility with a loss of less than
Basic Rate Interface Lines and Trunks
2 dB
— 2-wire non-VNL trunk facility with impedance
compensation
— 4-wire non-VNL facility
2 dB
— 2-wire non-VNL trunk facility when impedance
compensation is not provided
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Transmission Parameters