Lucent Technologies Release 6 manual Analog Line Circuit Protectors

DEFINITY Enterprise Communications Server Release 6	Issue 5
Installation and Test for Multi-Carrier Cabinets 555-230-112	May 1998

5Install and Wire Telephones and Other Equipment

Off-Premises or Out-of-Building Stations Page 5-33

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 5-11 shows the recommended protectors.

Table 5-11. Analog Line Circuit Protectors

Protectors

	Primary	Sneak Current
Primary1	(with heat coil)	Protectors2
3B1A (carbon)	4B1C (carbon)	220029 Fuse
3B1E-W	4B1E-W	SCP-1
(wide gap gas tube)	(wide gap gas tube)
3C1S	4C1S
(solid state)	(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.

2.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/telephones 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 TN746 Analog Line circuit packs