PRACTICE 553-2201-182
Table 2-D
RETURN LOSS (In-Service Requirements)
CONNECTION FROM CIRCUIT
ECHO
LOW/HIGH
NOTES
4W VNL TIE TERMINATION RETURN
SINGING
TRUNK TO THE
LOSS
RETURN
FOLLOWING:
LOSS
4W VNL Tie Trunk 4W legs of Hybrid
(through balance)
terminated in
600~
21
20/20
I,3
c
4W
Non-VNL Tie Trunk
(terminal balance)
600R •k 2.16
,AF
at
distant PBX
22
15/u
1.3
+
2W Non-VNL Tie Trunk
(terminal balance)
600R
i-
2.16
uF
at
distant PBX
18
lO/lO
1.5
CO or FX Trunk (terminal
balance)
900R
-k
2.16
,uF
at
co
18
lO/lO
2.5
PBX Station Line (terminal
balance)
SL-1 Station Line (terminal
balance)
600R
+ 2.16
,uF
24 18/18
1.4
600R 24 18/18
1.4
PBX Station Line (terminal
balance)
Station off-hook
-:
12
8/8
I,4
Note 1: Reference impedance is
600/900R
-I-
2.16
uF.
.-
Note 2: Reference impedance is
90011
i-
2.16
uF.
Note 3: Switchable pads set for nominal loss of 1
dB.
Note 4: Switchable pads set for nominal loss of 3
dB.
Note 5: If facility loss is
less
than 2
dB
or adequate impedance correction is not provided,
nominal loss has to be increased to 3
dB
by switching in the 2
dB
pad.
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