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Install Off-Premises Station Wiring
Issue 10 June 2005 135
Figure 63: Connections to 24 Out-of-Building Telephones
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 23
shows the recommended protectors.
Figure notes:
1. Locally engineered cables
2. Multi-pair protector units (primary
protectors with heat coils or equivalent
with sneak current protection)
3. B25A cable
4. Concentrator cable (WP90929 List 1)
5. 356A adapter
6. Out-of-building wiring
7. Out-of-building analog telephones
8. Part of MDF
9. Station side (white field)
10. System side (purple field)
11. Cross-connect jumpers
12. To TN2183, TN769, or TN746B
analog line circuit pack
crdf24o RPY 01239
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