Viking Electronics LSD-2 Line Sharing Device
Overview
The Viking Electronics LSD-2 is a hardwired line sharing device that lets you split a single analog phone line between a standard telephone and an emergency phone or priority alarm device — without running a second line or touching your PSTN provisioning. The LSD-2 holds 40V DC talk battery on the priority port, so when an emergency device goes off-hook, it seizes the line immediately regardless of what the standard phone is doing. For facilities managers and security integrators who need code-compliant emergency call capability without the cost of a dedicated line, this is the straightforward hardware answer.
Operating on a UL-listed 120VAC adapter that converts to 12VDC at 500mA, the LSD-2 draws from standard wall power and needs no specialty power infrastructure. The unit ships ready to wire: six screw terminals cover both phone line connections and device ports, keeping field termination clean and auditable. At 5.25" x 3.5" x 1.75" and 2 lbs, it fits inside a standard enclosure or mounts in a telecom backboard without consuming rack space.
Key Features
- Priority Line Seizure: The emergency phone or alarm device takes the line the moment it goes off-hook — the standard phone is cut out automatically. In a real emergency, there is no busy-signal problem and no manual intervention required.
- 40V DC Talk Battery: The LSD-2 supplies 40V DC on the priority device port, which meets the loop current and voltage requirements of most Viking emergency phones and third-party alarm dialers. You are not relying on the telco to deliver adequate loop voltage to the far device.
- UL-Listed Power Adapter Included: The included 120VAC to 12VDC 500mA adapter is UL listed, which matters for AHJ inspections in commercial and institutional facilities. No need to source a separate listed supply.
- Six Screw Terminals: All connections land on six clearly labeled screw terminals — line in, standard phone out, priority device out. No punch-down tools, no RJ11 punch blocks, no ambiguity during installation or troubleshooting.
- Compact Form Factor: At 5.25" x 3.5" x 1.75", the LSD-2 tucks into a surface-mount enclosure, inside an elevator phone cabinet, or behind a gate intercom panel without dominating available space.
- Broad Environmental Tolerance: Rated for 32°F to 90°F operation at 5% to 95% non-condensing humidity — covers conditioned interior spaces including equipment closets, lobbies, and stairwells. Not rated for unheated outdoor enclosures.
- Two-Year Limited Warranty: Viking backs the LSD-2 with a two-year limited warranty, consistent with their standard product line.
Integration & Compatibility
The LSD-2 works with any analog POTS line and is designed to pair with Viking Electronics emergency phones, entry systems, and elevator phones that draw loop current from a standard analog port. It is the correct insertion point between your analog telephone equipment and a priority alarm device when both must share one physical line. It does not interface with VoIP trunks, SIP adapters, or digital PBX station ports directly — if your facility runs IP telephony, you will need an ATA upstream of the LSD-2. For integrators building out emergency phone systems in parking structures, elevator cabs, or pool enclosures, the LSD-2 eliminates the need to provision and pay for a second analog line at each location. Pair it with an appropriate power supply and enclosure for a clean, inspectable installation.
Frequently Asked Questions
Q: Will the LSD-2 work with a VoIP or SIP line?
A: The LSD-2 is designed for standard analog POTS lines. For VoIP or SIP trunks, you would need an analog telephone adapter (ATA) upstream to convert to a standard analog loop before connecting the LSD-2.
Q: What is the warranty on the LSD-2?
A: Viking Electronics provides a two-year limited warranty on the LSD-2.
Q: Does the LSD-2 include a power adapter?
A: Yes. A UL-listed 120VAC to 12VDC 500mA adapter is included in the box.
Q: What happens if the standard phone is in use when the emergency device goes off-hook?
A: The LSD-2 gives priority to the emergency phone or alarm device. When the priority port goes off-hook, it seizes the line, displacing the standard phone connection automatically.
Q: Is the LSD-2 suitable for outdoor installation?
A: The LSD-2 is rated for 32°F to 90°F at 5–95% non-condensing humidity. It is intended for conditioned indoor spaces or weatherproof enclosures — not for direct outdoor exposure.
Q: How many screw terminals does the LSD-2 have?
A: Six screw terminals handle all wiring connections: the incoming phone line, the standard phone port, and the priority emergency device port.
The LSD-2 (also searched as LSD 2) solves a wiring problem that comes up constantly in facilities with existing single-line analog service: you need an emergency phone on the same line as a house phone, and you cannot get a second analog circuit approved or budgeted. The 40V DC talk battery spec is what actually matters here — it tells you the priority device will have adequate loop voltage to operate even at longer cable runs from the demarcation point.
Technical Highlights:
- 40V DC Talk Battery: Supplies loop voltage directly to the priority device port, ensuring compatible emergency phones and alarm dialers operate reliably regardless of telco line conditions at the site.
- UL-Listed 120VAC Adapter: The included adapter satisfies most AHJ requirements for listed components in life-safety-adjacent installations — one less item to source and document separately.
- Six Screw Terminals: All three ports (line, standard phone, priority device) land on screw terminals rather than modular jacks, which means direct conductor termination, no punch-down tools, and connections that stay put under vibration in elevator or gate enclosures.
Deployment Considerations:
- The 32°F to 90°F operating range rules out unheated exterior enclosures in cold climates — if you are mounting in a parking structure or exterior gate cabinet that sees freezing temps, you need a heated enclosure around the LSD-2.
- The LSD-2 passes analog loop current only. SIP ATAs, digital PBX extensions, and T1/PRI circuits are incompatible upstream — confirm analog POTS delivery before specifying this unit.
The right call for elevator cab phones, parking structure emergency stations, and pool-area call boxes where a single analog line serves both a standard house phone and a code-required emergency device — and where running a second line is not an option.
