Spec Sheet Preview: The Alpha Communications® LI424B strobe is a high-intensity remote visual signaling device which is typically used with the Alpha Communications® IA543 amplifier apartment intercom systems, and optionally with the Alpha Communications® IA502 multi-entrance transfer relay(s). Due to its versatility, the LI424B can also be used as a stand-alone device, which can be triggered by a dry contact pushbutton or dry contact relay closure. The unit is primarily for use in locations where hearing-impaired persons require supplemental call notification, but can be used anywhere that a vis ...