Lucent Technologies 555-230-128 manual Analog Line Circuit Protectors

DEFINITY Enterprise Communications Server Release 6	Issue 3
Installation and Test for Compact Modular Cabinets 555-230-128	May 1998
1 Install and Cable the Cabinets
Install Off-Premises Station Wiring	Page 1-87

Circuit Protectors

Carbon block, or equivalent protection is required at both building entrances. Also sneak current protection is required. Protection can be provided by a 4-type protector or a 3-type protector plus a separate sneak current protector. The 4-type protector is equipped with a heat coil.

The 4-type protector is the preferred device. For installations not using primary protection, 4-type protectors should always be used. When the 3-type protector is already installed, a separate sneak current protector is required. The multi-pair protector units and the off-premises cabling must be locally engineered.

Connectorized multi-pair protector units (female 25-pair connector) are recommended. Table 1-14 shows the recommended protectors.

Table 1-14. Analog Line Circuit Protectors

Protectors

	Primary	Sneak Current
Primary1	(with heat coil)	Protectors1
3B1A (carbon)	4B1C (carbon)	220029 Fuse
3B1E-W (wide gap	4B1E-W (wide gap gas tube)	SCP-1
gas tube)
3C1S (solid state)	4C1S (solid state)

1.The 3-type protectors should only be used if they are already part of the existing protection system. A sneak current protector is always required when a 3-type primary protector is used.

The maximum range of out-of-building analog telephones (500-, 2500-, or 7100-types) connected to an analog line circuit pack should be such that the maximum loop resistance does not exceed 1300 Ohms.

The following voice terminals cannot be installed in an exposed environment:

■7300-type voice terminals connected to TN762 Hybrid Line circuit packs

■Multi-button Electronic Telephone (MET) sets connected to TN735 MET Line circuit packs

■Analog telephones connected to TN746 Analog Line circuit packs

Refer to Table 1-1 on page 1-3 for circuit protector ordering information (comcodes).