Wanderbox installation guidePage 23
Figure-8: FXO port circuit example
Primary protection must be provided externally to the Wanderbox unit.
4.6 FXS interface protection circuit
The FXS port line interface circuit is shown in Figure-6 below.
Both over-current and overvoltage devices are provisioned on each line interface.
The overvoltage protection device, Littlefuse P1301, will clamp at V(drm) = 120V
Figure-9: FXS port circuit example
Primary protection must be provided externally to the Wanderbox unit if the wiring leaves
the premises.
4.7 Primary Surge protection
Primary surge devices must be provisioned externally to the Wanderbox, to provide co-
ordinated protection for the Comma interfaces in conjunction with the secondary protection
that is built into the unit.
Wanderbox does NOT support primary protection levels for interfaces exposed to outdoor
environments.
Far South Networks recommend installation of primary surge protection devices (GDT –
Gas Discharge Tube) installed on all analogue lines exposed to extra-building conditions.
These devices are described below.
4.7.1
FXS interface
Voltage = 130Vdc, transient = 10kA 8/20, response <25nS
Recommended part:
Clearline KP1HS (12-00663) – single line solution
Clearline KP2HS (12-00196) – 10 line solution
Surgetek: DPL 10F/TEL-ISDN – 10 line solution
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