Page 662 of 906 NT8D15 E&M Trunk card553-3001-211 Standard 3.00 August 2005trunks. The class of service determines the operation of the switchable padscontained in each unit. They are assigned as follows:• TRC for a 2-wire non-VNL trunk facility with a loss of greater than2 dB, or for which impedance compensation is provided, or for a 4-wirenon-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 throughconnections and the actual port-to-port loss introduced for connectionsbetween 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 209Pad switching algorithmPort BPort B pads E&M Trunk Pads Port-to-port loss (dB)TransmitD to AReceiveA to DTransmitD to AReceiveA to DPort B toE&ME&M toPort BIPE line N/A N/A Out In 2.5 3.5Universal trunk(TRC)Out Out In In 0 0IPE TIE (VNL) In Out In Out 0 0Note: Transmit and receive designations are from and to the system. Transmit is from thesystem to the external facility (digital-to-analog direction in the E&M trunk card). Receive is tothe system from the external facility (analog-to-digital direction in the E&M trunk card).
