Return Loss - Nortel Meridian 1 Succession 1000 Manual

Return loss

Table 43
Return loss—in-service parameter values—A-Law (Part 1 of 2)
Connection
Line interfaces:
Line side
4-wire trunk side
Note 1: Terminating impedances are 600 ¾ for a regular line and 600 ¾ and 2.16 µF for a PBX
line.
Note 2: Terminating impedances are 600 ¾ for a regular line and 900 ¾ and 2.16 µF for a
PBX line.
Note 3: Terminating impedances are 600 ¾/900 ¾ and 2.16 µF for a 2-wire trunk.
Note 4: Terminating impedances are 600 ¾ for a regular line and a 4-wire trunk.
Note 5: The design requirements in this table are intended to ensure the satisfaction of the
in-service requirements in Table 44.
Transmission characteristics—A-Law
Return loss at an impedance discontinuity in a transmission path is the ratio,
in decibels, of the power level of an incident signal to the power level of the
resulting reflected signal. Echo return loss (ERL) is a weighted average of the
return loss values over the frequency range of 500 to 2500 Hz.
Single-frequency return loss (SFRL) is the lowest value of nonweighted
return loss occurring in the frequency range of 200 to 3200 Hz.
Table 43 shows return losses guidelines to satisfy the in-service requirements
shown in Table 44. For each interface type (line and 2-wire trunk), a
connection is made through the PBX to a 4-wire trunk interface, and the
return loss is measured at both interfaces. All terminating impedances are 600
ohms.
Echo return loss (dB)
Single-frequency
>18
> 21
Page 157 of 236
return loss (dB)
(300–3200 Hz)
> 12
> 19
Transmission Parameters
Notes
1
2