Ordering Guide; 2520B Telephone Set (Touch-Tone Dial); Identification - Lucent Technologies 520B Manuel D'utilisation

To replace the apparatus unit, remove all dirt and grit from threads of both base and apparatus unit. Apply
anti-seize compound (RM-642708) to the threads, and screw the unit to the base with a minimum of eight
turns until the leaf springs of base make contact with the apparatus unit. Align the apparatus unit with the
base to permit depression of the locking pin into the hole in the base. Depress the locking pin and tighten
the No. 8-32 Allen Setscrew. The cover may now be secured to the apparatus unit by means of the three
mounting screws.
After ensuring that all defects due to any cause, even though seemingly slight, have been corrected,
reconnect line wires at the protector.

Ordering Guide

520B Telephone Set, 520B-03 Black —
Comcode: 103873048
Handset, G11A4-Type (with cord) —
Comcode: 101942969
Handset, G11A9-Type (with cord) —
Comcode: 101942977
Universal 8CB-Type Dial —
Comcode: 103759767
Switchhook Assembly —
Comcode: 840404628

2520B Telephone Set (Touch-Tone Dial)

WARNING: Under no circumstances is telephone apparatus or wiring to be installed in a
location where acetylene gas may become present in the atmosphere.
The 2520B telephone set is equipped with a 72H-3A2 Touch-Tone Dial. This set is intended for use in
hazardous (explosive atmosphere) locations.

Identification

The 2520B telephone set consists primarily of two major components: an apparatus unit and a base.
These parts are made of high tensile strength aluminum alloy to withstand any explosion within the
telephone set.
The base provides an external projection to engage corresponding threads in the apparatus unit. It also
provides spring-type contact terminals for line and ground connectors.
The apparatus unit, which screws onto the base, contains the telephone set components. Three
projecting studs located on the back of the apparatus unit make contact with the three spring terminals in
the base, thus carrying the line and ground connections into the unit. The apparatus unit cannot be locked
unless the locking pin is engaged in the locking hole in the base of the set.
The 2520B telephone set and associated apparatus unit is equipped with a G11A4 handset (4-foot cord).
The 2520B telephone set is designed for wall mounting. It is recommended that the telephone not be
directly mounted on drywall.
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