BLK-4 - Viking Electronics

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Line Status LED Strobe / Beacon Light Kit Mass Notification System

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Product Details

The BLK-4 provides high visibility indication of analog line status through a high powered LED strobe and / or beacon visual indicator. The BLK-4 is the ideal solution for the hearing impaired and can be used equally well in loud warehouses or factories, where ringing phones cannot be heard. Alternatively, the BLK-4 can be used to add emergency notification to pre-existing emergency phones by turning on the strobe light when the emergency phone is in use.

The included control module has a disable input which is ideal for two-button emergency phones, such as Viking’s E-1600-20A, allowing “Info” button calls to be placed without activating the relay (turning on the emergency strobe light, camera, etc.).

Four DIP switches are provided for turning ring detection on or off, off-hook / loop detection on or off, 12VDC or dry relay contact output, and for selecting a ring cadence mode which allows the relay to follow ringing or to remain activated during the off time of standard ring cadence. The control module can be installed on any standard telephone line or analog PABX / KSU station. The strobe can be interfaced to flash on ringing, off-hook or a combination of ringing and off-hook (line in-use).

For outdoor installations where the unit is exposed to precipitation or condensation, use model BLK-4-EWP. For more information on Enhanced Weather Protection (EWP), see DOD 859.

The BLK-4 includes: (1) control module, (1) SL-2 blue LED strobe light, (1) 12VDC power adapter, (16) gel-filled butt connectors and (1) single gang weatherproof mounting box with gaskets and hardware.


  • Ringing phone or TTY indication for the hearing impaired
  • Ringing phone indication in loud warehouses and factories
  • Emergency illumination for emergency phones in elevators, campuses, hallways, parking ramps, etc.
  • Alarm indication for security systems or alarm panels with phone dialers



  • Durable polycarbonate lens
  • High-output long life LED technology
  • Four programmable flash patterns:
    • Single Flash
    • Double Flash
    • Quad Flash
    • Flicker Flash
  • 6 programmable beacon and strobe brightness settings
  • Immune to shock and vibration
  • Flush mount or surface mount with weatherproof single gang box (included)
  • 0.75″ knockouts for connecting conduit, etc.
  • Strobe and control module may be installed separately
  • Can be configured to signal: ringing, off-hook, a combination of both ringing and off-hook (line in-use), or triggered from a contact closure
  • SPDT relay contacts provided
  • Selectable ring cadence mode: strobe light will remain flashing between rings
  • Switched 12VDC output: follows relay activation for powering strobe lights, cameras, etc.
  • Disable input, ideal for use with two-button emergency phones like Viking’s E-1600-20A (DOD 215), will not activate strobe light on “Info” calls


  • Power: 120VAC / 12VDC 500mA UL listed adapter provided
  • Maximum Power Supply Run Length on CAT-5:
    • 1 pair = 125 ft
    • 2 pair = 225 ft
    • 3 pair = 325 ft
    • 4 pair = 475 ft
  • Maximum SL-2 Wire Run Length on CAT-5:
    • 3 wires = 100 ft
    • 6 wires = 300 ft
  • Strobe Dimensions: 4.38″ diameter x 2.75″ (111mm diameter x 69mm)
  • Control Module Dimensions: 2.9″ x 2.1″ x 1.0″ (74mm x 53mm x 25mm )
  • Shipping Weight: 3.3 lbs (1.5 kg)
  • Operating Temperature: -15°F to 130°F (-26°C to 54°C)
  • Humidity: 5% to 95% non-condensing
  • SPDT Relay Contact Rating: 1A @ 30VDC / 0.5A @ 125VAC, 250VAC maximum
  • Minimum Loop Current: 15mA
  • Minimum Ring Voltage: 25VRMS
  • REN: 0.5A
  • Disable / Info Switch Input: 50mA / 80mW maximum
  • Strobe Flash Rate: 60 flashes per minute (default)
  • Maximum Strobe Light Output @ 15VDC:
    • Clear lens: 323 lumens
    • Amber lens: 242 lumens
    • Blue lens: 116 lumens
    • Red lens: 66 lumens
  • Mounting: Fasten to wall, post, etc. with included surface mounting hardware
  • Connections: Color coded wires with (16) gel-filled butt connectors

Spare Parts