Matrix M12 to RJ11 Cable/B3 - 10ft

What This Cable Does

The Matrix M12 to RJ11 Cable / B3 is a purpose-built adapter that runs dimming signal between a Matrix LED or HID fixture and a grow light controller equipped with an RJ11 output port. The M12 end locks securely into the control port on the fixture — a locking industrial connector format that resists accidental disconnection under the vibration and activity common in active grow rooms. The RJ11 end seats into the controller's dimming port, carrying the analog control signal that sets intensity across the zone.

Within the Matrix cable lineup, the B-series designates M12-to-RJ adapter cables specifically, while the '3' in B3 indicates the 3-pin M12 configuration used on the fixture end. This distinguishes it from the B4 variant (M12 to RJ12, 4-pin), so confirming your fixture's control port pin count before ordering is important. The 10-foot run gives enough slack to reach a wall-mounted or rack-mounted controller from most standard fixture hang heights without excess cable management overhead.

Where It Fits in a Matrix Lighting Install

Matrix controllers — including the MC2 and MX2A — connect to fixtures through M12 control ports. In a standard single-zone setup, this B3 cable runs from the controller's RJ11 output directly to the first fixture in the chain. For multi-fixture zones, fixtures are then linked to each other using M12 daisy chain cables (A3 or A4 series), with this B3 cable serving as the head-of-chain connection between the controller and fixture one.

Matrix controllers can manage up to 80 fixtures per channel via 0-10V dimming, making correct cabling at the controller-to-fixture handoff critical. A loose or mismatched connector at this junction breaks dimming signal to the entire zone. The locking M12 connector on this cable eliminates that failure point. For facilities running multiple controller zones across a large canopy, one B3 cable is needed per active controller channel.

Construction and Environment Suitability

The M12 connector format used across the Matrix cable family is an industrial-grade, locking connector standard built for continuous operation in demanding environments — including the elevated humidity, condensation risk, and repeated cable movement typical of commercial cultivation facilities. The locking mechanism on the M12 end provides a secure, positive-seating connection that minimizes signal degradation and won't back out during normal room activity.

At 10 feet, this cable is the standard length in Matrix's B-series and covers the typical vertical and horizontal distance between a ceiling-hung fixture and a wall- or column-mounted controller in most single-tier and vertical grow configurations. If greater reach is required between the controller and the first fixture, pair this cable with an M12 extension (C3 series) rather than substituting a non-OEM cable, which risks impedance mismatch or pin incompatibility.

Ordering the Right Cable

The Matrix M12 cable lineup includes several distinct variants: A3/A4 daisy chain cables for fixture-to-fixture links, B3/B4 adapter cables for controller-to-fixture connections (RJ11 and RJ12 respectively), and C3/C4 extension cables for added reach. The B3 (this cable) is specifically the controller-to-fixture adapter for fixtures using a 3-pin M12 control port with an RJ11 controller output. If your controller outputs RJ12, the B4 is the correct cable.

HSC carries the full Matrix cable family. If you're building out a new zone, retrofitting an existing room, or replacing a damaged cable, contact us with your fixture model and controller model and we'll confirm the correct cable or cable combination for your layout before you order.