Specifications

Surge Protectors
Surge protection is strongly recommended if the MS/TP bus is wired between buildings. The protection is provided
by a voltage surge suppressor, which is installed on the MS/TP bus near the MS/TP device. Example applications
are shown in Figure 22.
Figure 22: Surge Protector Installation on MS/TP Bus
Note: Fiber-optic bus connections between buildings are immune to transient voltage and other problems associated
with hard-wire bus connections. Fiber-optic bus connections do not require surge protection and may be less
costly to install. See Fiber-Optic Modems for information.
The recommended surge protector is the Transient Eliminator, model TE/JC04C12, manufactured by Advanced
Protection Technologies, Inc. (APT). The device protects the MS/TP bus from indirect lightning, and shunts both
common and normal mode voltage surges to ground repeatedly without damage to MS/TP bus components.
Important: The surge protector is capable of protecting the MS/TP bus from indirect lightning strikes, not direct
lightning strikes. A direct strike may cause actual damage to the bus cable or surrounding property.
An indirect lightning strike may cause induced voltage transients that could cause electronic malfunction
without visible damage to equipment if the equipment were not protected.
Use the surge protector with the standard MS/TP bus wiring. Do not use it with any other type wiring such as leased
line. If you need surge protection for other wire types, contact APT or another transient noise protection company.
Table 16 lists the specifications of the surge protector.
Table 16: Surge Protector Specifications
SpecificationCategory
Transient EliminatorProduct Name
Surge ProtectorGeneric Name
TE/JC04C12Model Number
Three stage solid-state design using both metal oxide varistors
and silicon avalanche diodes for suppression
Design
Less than 1 nanosecondResponse Time
10 kA per conductorMaximum Impulse Current (8/20 ms current impulse)
44MS/TP Communications Bus Technical Bulletin: Appendix: FC Bus Auxiliary Devices