Alpha LI424BP Specsheet

The LI424B Strobe is used primarily in conjunction with an entry intercom or video-intercom system, to enable a
Hearing-Impaired resident of an apartment to visually see that they are being called from a door entry station. The
built-in timing circuit enables the LI424B to flash from approx. 20 to 35 seconds, depending on the amperage and
current provided, so a resident is sure to see the visual signal, even if the calling pushbutton is only depressed for a
brief period of time. The LI424B can also be used as a stand-alone visual signaling device, when used with a separate
24VDC power supply and a dry contact pushbutton/switch or relay. When powered by the IA543 apt. intercom amplifier,
a maximum of one (1) strobe should be conencted in each apartment/suite. When using a separate 24VDC power supply,
multiple strobes can be mounted from a single dry contact pushbutton or relay contacts.

Before applying power to the system, make certain that all wires are free from shorts or grounds. Failure to do so could
result in damage to the system devices. The LI424B is not a weather resistant device and is not designed to be installed
outdoors. Using this unit in areas of high humidity, direct sunlight, or high ambient light will minimize the effectiveness
of this strobe. Failure to install as per factory instructions may result in the voiding of the warranty.

The LI424B strobe mounts in a standard 4-inch electrical box. If the LI424B is to be used as a primary visual indicator,
locate the box(es) at a minimum of 6' (1.8m) from the floor or 6" (15cm) from the ceiling. It is recommended that the wiring
into the 4-inch square electrical box be done from the back or sides and not the top or bottom, to allow clearance for the
plastic adapter ring that mounts inside the box.

Typical Wiring for the LI424B
strobe when triggered from a
dry contact switch or relay contact

NOTE: terminals shown may not be in the
order that they appear on the equipment.

Wiring diagram for the LI424B Strobe for
the Hearing-Impaired showing both stand-

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alone 24VDC wiring and when used with
the IA543 apt. intercom amplifier.

AWD246 Rev. 1 (07/2017)

Typical Wiring for the LI424B
strobe when used with the IA543
Apt. Intercom Amplifier

*

NOTE: terminals shown may not be in the
order that they appear on the equipment.

* - 3-wire and 5-wire stations may also be used
by connecting the 'X' terminals as shown above