Nortel Networks 553-3001-211 manual On page 651 shows the pad switching orientation

Page 650 of 894 NT8D15 E&M Trunk card

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 204 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 152 on page 651 shows the pad switching orientation.

Table 204

Pad switching algorithm

	Port B pads		E&M Trunk Pads		Port-to-port loss (dB)
	Transmit	Receive	Transmit	Receive	Port B to	E&M to
Port B	D to A	A to D	D to A	A to D	E&M	Port B
IPE line	N/A	N/A	Out	In	2.5	3.5
Universal trunk	Out	Out	In	In	0	0
(TRC)
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).

553-3001-211 Standard 2.00 September 2004