100
Cabling the G600 Media Gateways
October 2002
Install Off-premises Circuit Protection
Protection from hazardous voltages and currents is required for all off-premises (out of
building) trunks, lines, and terminal installations. Both over-voltage protection (lightning,
power induction, and so forth) and sneak current protection are required. Sneak current
protectors must be either UL listed/CSA certified, or must comply with local safety standards.
Sneak current protectors must have a maximum rating of 350 mA and a minimum voltage rating
of 600 V, or as required by local regulations. The following devices protect the system from
over-voltages:
• Analog trunks use the 507B sneak protector or equivalent. Over-voltage protection is
normally provided by the local telephone company.
• Analog voice terminals use one of the following types of combined over-voltage and
sneak current protection, or equivalent:
— Carbon block with heat coil for UL code 4B1C
— Gas tube with heat coil for UL code 4B1E-W
— Solid state with heat coil for UL code 4C1S
• DCP and ISDN-BRI terminals use the solid state 4C3S-75 with heat coil protector, or
equivalent.
• DS1/T1 circuits require isolation from exposed facilities. This isolation may be provided
by a channel service unit (CSU) (T1), or other equipment that provides equivalent
protection.
Install Sneak Fuse Panels
Sneak current protection is required between the incoming RJ21X or RJ2GX network interface
and the system for both trunk and off-premises circuit packs. The model 507B sneak current
fuse panel, or equivalent, is recommended for sneak current protection. See ‘‘Model 507B
sneak fuse panel’’ on page 101.
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