Nortel Circuit Card, Installation Manual, Page: 662 / 908

Page 662 of 906 NT8D15 E&M Trunk card
553-3001-211 Standard 3.00 August 2005
trunks. The class of service determines the operation of the switchable pads
contained in each unit. They are assigned as follows:
• TRC for a 2-wire non-VNL trunk facility with a loss of greater than
2 dB, or for which impedance compensation is provided, or for a 4-wire
non-VNL facility.
• NTC for a 2-wire, non-VNL trunk facility with a loss of less than 2 dB,
or when impedance compensation is not provided.
See Table 209 for the pad switching control for the various through
connections and the actual port-to-port loss introduced for connections
between the E&M trunk card and any other IPE port designated as Port B.
Figure 155 on page 663 shows the pad switching orientation.
Table 209
Pad switching algorithm
Port B
Port B pads E&M Trunk Pads Port-to-port loss (dB)
Transmit
D to A
Receive
A to D
Transmit
D to A
Receive
A to D
Port B to
E&M
E&M to
Port B
IPE line N/A N/A Out In 2.5 3.5
Universal trunk
(TRC) Out Out In In 0 0
IPE TIE (VNL) In Out In Out 0 0
Note: Transmit and receive designations are from and to the system. Transmit is from the
system to the external facility (digital-to-analog direction in the E&M trunk card). Receive is to
the system from the external facility (analog-to-digital direction in the E&M trunk card).