Figure 12: 86445-32 2W Fxs Unit Loopbacks - GE JungleMUX 86445-31 Technical Practice And Installation Manual

Splitting mode disconnects the drop side of the circuit (upon
insertion of test jack) and allows tones to be injected and measured
for end-to-end or loopback testing.
Loopback
May be set for None (loopback off), Local or Line (remote). The
loopback feature is used for test/maintenance purposes only.
In Local Loopback mode, the unit internally loops the VF signal
back to the VF interface at the digital side of the CODEC (Figure
12a). In this mode, a tone injected locally can be measured on the
unit's receive side.
In Line (remote) loopback mode, the unit internally loops the signal
back towards the far-end unit at the digital side of the CODEC.
This means that a signal transmitted from the far-end will be looped
back to the far-end. This allows to inject a tone from a VF Test Set
connected to the far-end unit and measure the tone received at the
far-end unit (Figure 12b). Note that if an external hybrid function
cannot be provided for testing, then an 86444 4W VF unit may be
used for testing purposes (Figure 12c).
Figure 12: 86445-32 2W FXS Unit Loopbacks: (a) Local
Loopback; (b) Line Loopback with 2W FXO or 2W FXS unit at far
Copyright  GE Multilin Inc. 2002
2W FXS 2W FXS
XMT XMT
2W 2W 2W
A/D A/D
2W 2W
VF VF
RCV RCV
D/A D/A
4W 4W 4W
NEAR END NEAR END
2W FXS 2W FXS
XMT XMT
2W 2W 2W
A/D A/D
2W 2W
VF VF
RCV RCV
D/A D/A
4W 4W 4W
NEAR END NEAR END
2W FXS 2W FXS
XMT XMT
2W 2W 2W
A/D A/D
2W 2W
VF VF
RCV RCV
D/A D/A
4W 4W 4W
NEAR END NEAR END
end; (c) Line Loopback with 4W VF unit at far end
342-86400-445PS
Issue 4.0
October 2006
Page 68
2W FXO/FXS 2W FXO/FXS
RCV RCV
4W 4W 4W
D/A D/A
XMT XMT
A/D A/D
2W 2W 2W
FAR END FAR END
(a) (a)
2W FXO/FXS 2W FXO/FXS
RCV RCV
4W 4W 4W
D/A D/A
XMT XMT
A/D A/D
2W 2W 2W
FAR END FAR END
(b) (b)
4W VF 4W VF
RCV RCV
D/A D/A
XMT XMT
A/D A/D
FAR END FAR END
(c) (c)
2W 2W
VF VF
2W 2W
VF VF
4W 4W
VF VF